What should I do when a computer freezes?

 

This document contains recommendations on what to do if the computer freezes or dead locks. If your computer has stopped responding, follow the steps below to attempt to get the computer to unfreeze.

Tip: If you are concerned about an important document that hasn't been saved, the program you are using may have an AutoSave feature, and you may be able to recover a recent version of the document after rebooting.

Note: If your program does not have an AutoSave feature or the ability to recover a recent version of a document, you may lose all unsaved work due to a freeze or dead lock. It is important to save your work often to minimize or prevent this possibility.

Give the computer some time

Wait. Give the computer a few minutes to process. Sometimes a computer may appear to be froze, but it is really just slow or busy processing a complex task.

Is the computer dead locked?

See if the computer can respond to anything by pressing the Caps Lock key on the keyboard and watching the Caps Lock led (light) to see if it turns off and on. If the computer can turn on and off Caps Lock, continue to the next step. If nothing happens, the computer is dead locked, and you must reboot the computer.

End Task the Not Responding program

If the Caps Lock can turn off and on, Windows is still working, but another program may not be responding and causing the computer to freeze. Press Ctrl + Alt + Del to open the Windows Task Manager. If the Task Manager can open, highlight the program not responding and choose End Task, which should unfreeze the computer.

Note: It could still take ten to twenty seconds for the unresponsive program to be terminated after you choose End Task.

Reboot a frozen computer

If none of the above steps helped, you must reboot the computer. To reboot a frozen computer, press and hold down the power button until the computer turns off. Once the computer is off, wait a few seconds, then turn the computer back on and let it start as normal.

Note: During the computer startup process, you may see a screen asking if you want to start the computer in Safe Mode or Start Windows Normally. Choose the Start Windows Normally option and see if Windows starts up correctly, without error.

Resolve Hardware or Device Driver issue

If after trying all of the above there may be defective hardware or a device driver is not working correctly. A defective hard drive, stick of RAM, video card, or other piece of hardware can cause a computer to freeze. A device driver can also cause a computer to freeze if it is out of date, conflicting with another driver, or just not working properly.

If you determine that a defective piece of hardware is causing the freezes, you should replace the hardware right away, to prevent further damage to the computer. If a device driver is at fault, you can try to download the latest driver from the manufacturer's website and install it before the computer freezes, or use another computer to download the driver and try installing the driver on your computer.

If you are unable to install the latest driver before the computer freezes, another option is to start the computer in Safe Mode. Once in Safe Mode, you can access Device Manager and uninstall the hardware device corresponding to the device driver that is not working correctly. Then, restart the computer and load into Windows normally. Windows should detect the hardware that you uninstalled and try to reinstall the device driver. This process may be enough to fix the issue and stop further freezes from occurring. You can also try installing the latest driver at this point, to make sure your computer is up-to-date for that device driver.

You can also try accessing the computer BIOS and disabling any hardware that is working properly, to see if that stops the freezes from occurring. However, you should still replace that hardware, as you may not be able to use your computer fully if the hardware remains disabled.

Take PC to Repair Shop

If none of the above options work or are possible to try, we recommend you take your computer to a computer repair shop and allow a computer technician to diagnose and fix the problem.

Windows error "Data or no disk loaded" with audio CD Bad or non audio CD is inserted

 

Make sure the CD you have currently in the computer is not bad or being misread by the computer by inserting another known good audio CD into the computer.

If another audio CD works it is likely either that the CD is dirty or may be an enhanced CD incompatible with the CD Audio player. Steps on properly cleaning a CD can be found on our cleaning page.

MCI CD audio driver not installed or is corrupt

If no audio CD is working in the computer but other CDs work fine, it is likely that the MCI CD audio driver is not installed or is corrupt on the computer.

• CD-ROM not working in Windows 9x, 2000, or XP.

To reinstall or install the MCI CD audio drivers follow the steps below:

1. Click Start, Settings, Control Panel
2. Double-click on Multimedia
3. Click the Advanced tab or Device tab.
4. Double-click Media Control Devices.
5. Double-click CD Audio Device (Media Control).
6. If this device is present and no audio CDs are working, click remove on the general tab in CD Audio Device (Media Control) properties.
7. Close out of all open Windows to get back to the Control panel
8. In Control panel double-click Add New Hardware.
9. Click Next, select No, click Next -- In the box listing the available hardware, select Sound Video and Game controllers and click Next.
10. In the Manufacturers box select Microsoft MCI.
11. In the Models box select CD Audio Device (Media Control).
12. Click Next and Finish.
13. Once Windows has completed the installation of the new device, reboot the computer.

No display on the monitor

Tip: The following is monitor troubleshooting and not for users who get readable picture when it is first load but then gets distorted when opening Windows.

Monitor is not on

Make sure the monitor is on. If no power LED (green or orange light) is seen on the monitor display try pressing the power button until it comes on. If no light comes on after several attempts continue to below connections not connected properly.

Computer is asleep

If your computer monitor was on and you stepped away from the computer and upon returning it was black it's likely that the computer is asleep. Try moving your mouse, clicking the mouse buttons, or pressing any key (space bar) on the keyboard to wake it up.

Connections not connected properly

 

Make sure that you are connecting the monitor to the back of the computer in the 15-pin connector as shown to the right or older computer 9-pin connection.

Note: Newer computers may be using a DVI or HDMI cable for the monitor.

If the computer is properly plugged in, make sure it is getting power.

If you are not receiving power from a known working wall outlet and if the power cord is removable, replace it with the one connected to the computer and power on the monitor again. If the monitor still does not get power or it is not removable, it is recommended that the monitor be replaced or serviced at a local TV or computer repair shop.

If the monitor is receiving power, check the LED status light.

If the light is orange or flashing ensure that the monitor is not in a suspend mode by moving the mouse or pressing a key on the keyboard. If the computer does not get a display by moving the mouse or touching the keyboard, turn off the computer and monitor and reconnect the data cable from the back of the computer, and if removable, the back of the monitor. Turn the computer back on; if you still encounter the same issue, continue reading through the other possibilities.

Monitor settings are not correct

Verify the brightness and contrast is turned up or adjust the brightness and contrast. If adjusting the brightness or contrast has no affect on the monitor continue reading through the other possibilities.

No POST

Does the computer beep when it is powered on or does it appear that the computer has activity? If the computer does not beep or beeps abnormally the computer is experiencing a hardware issue or is exhibiting a No POST. Run through the POST troubleshooting steps to determine the failure.

Hardware Issue

If you have followed the above recommendations and are still encountering the same issue, it is likely that the computer may have either a bad video card or monitor. The best method of determining this is to do one or both of the following:

• Disconnect your monitor and connect it to another computer. This can be a friend or family's computer or it can be taken to a service center.
• Borrow a computer monitor and connect it to your computer. This will not harm the other computer monitor in any way.

If your monitor works on another computer it is safe to assume that the video card or potentially the motherboard within the computer is bad.

 

some common error codes and how to fix them

 Windows Error Codes and How to Fix them

While working with an operating system, it is not uncommon to encounter errors. Some errors that occur frequently on a Windows system are compiled in a common Windows error codes list. It may not be difficult to fix the common Windows errors but for certain errors, some level of expertise or an in-depth knowledge of the Windows OS may be required. A consolidated list of common windows problems and solutions is useful for a user when they encounter an error. A common Windows error codes list provides a quick and a easy reference and also a possible solution to fix a common Windows error.

Common Windows Error Codes and How to Fix them!

Below is a list of the most common error codes that you may face while using Windows and its basic components. Some solutions have been provided for you to try to solve them. You should also note that some require the assistance of a computer technician and you should not try to fix them yourself as they could seriously damage your computer system.

• Error #0

Error Message: Connection Successful!
Solution: Does not require any action.

• Error #2

Error Message: System cannot find specified file
Solution: You should reinstall NCP & DUN

• Error #5

Error Message: Access Denied
Solution:
1. Ensure that you have entered the right username and password in the field labeled "domain" for NT/2k
2. Check that the option "accept any authentication including clear text" is activated

• Error #5

Error Message: Invalid Procedure Call
Solution: Dialup and Network components must be installed again

• Error #6

Error Message: Stack Overflow
Solution:
1. Try cold booting your computer
2. If this does not work, the problem might come from your RAM or the Swap file

• Error #20

Error Message: The system cannot find the specified device
Solution:
1. Ensure that the right modem has been selected
2. If it does not respond, try to reinstall it
3. You can also try to reinstall NCP/DUN/RAS

• Error #71

Error Message: No more connections are allowed
Solution:
1. Someone else might have connected under your account
2. If you have been ghosted on the server, your Internet Service Provider can bump the ghost program off

• Error #380

Error Message: Invalid Proper Value
Solution:
1. Autodial should be pointed to the correct dialler
2. Else, set up the dialler again

• Error #600

Error Message: An operation is pending
Solution:
1. You should first try rebooting your computer
2. Ensure that no other program is using your modem
3. Else, press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem
4. Make sure that your computer is Spyware free

• Error #601

Error Message: The port handle is invalid
Solution:
1. Select the modem's COM port and under the Diagnosis section, open "More Info". You should reboot your computer if you are able to get ATI responses, remove the erroneous init string or enter ATZ as the init
2. You can also reinstall your modem
3. Else press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem
4. Your Dialup Networking should be reinstalled together with its components
5. Your modem might not be working properly. You should then consult your computer manufacturer

• Error #602

Error Message: The port is already open
Solution:
1. Try to reboot your computer
2. Ensure that no other program is using the modem
3. Else press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem
4. Try uninstalling the AOL Adapters in the Network Control panel and reboot your computer. Install your Dialup Adapter again
5. Remove the erroneous init string or enter ATZ as the init
6. If you have Quicken 2000, deactivate the Quicken Download Manager
7. Try installing your modem again
8. Make sure that your computer is Spyware free

• Error #603

Error Message: Caller's buffer is too small
Solution:
1. Ensure that your port is not configured to a low speed
2. In your "Port Settings", ensure that FIFO is not set to low
3. Try reinstalling your Dialup Networking together with its components
4. If you are still having problems, contact your computer manufacturer

• Error #604

Error Message: Wrong information specified.
Solution:
1. Ensure that the are no outages in your area
2. Try to enter the username and password again
3. Set up the dialler again
4. Your Dialup Networking should be installed again together with its components
5. You can also try to reinstall your modem

• Error #605

Error Message: Cannot set port information.
Solution:
1. Ensure that the are no outages in your area
2. Try to enter the username and password again
3. Set up the dialler again
4. Your Dialup Networking should be installed again together with its components
5. You can also try to reinstall your modem

• Error #606

Error Message: The port is not connected.
Solution:
1. Select the modem's COM port and under the Diagnosis section, open "More Info". You should reboot your computer if you are able to get ATI responses, remove the erroneous init string or enter ATZ as the init
2. You can also reinstall your modem
3. Else, press Ctrl-Alt-Delete and if RNAAPP loads, contact a technician to fix this problem
4. Your modem might not be working properly. You should then consult your computer manufacturer if the problem persists.

• Error #607

Error Message: The event is invalid.
Solution:
1. If this problem arises while dialling up to the internet, verify that the settings of the event log have been correctly set
2. Try rebooting your system and ensure that the dialler/network settings have been correctly configured
3. Else, install RAS/DUN again

• Error #608

Error Message: The device does not exist.
Solution:
1. Check that the right modem is set in the dialler
2. Ensure that you are using the right modem drivers by checking the modem diagnostics. If it's not the case, set up the correct drivers.
3. Reinstall the dialler
4. Your modem might not be working properly. Try reinstalling it
5. You should consult your computer manufacturer if the problem persists

• Error #609

Error Message: The device type does not exist.
Solution:
1. Check that the right modem is selected in the dialler
2. Ensure that you are using the right modem drivers by checking the modem diagnostics. If it's not the case, set up the correct drivers
3. Your modem might not be working properly. Try reinstalling it
4. You should consult your computer manufacturer if the problem persists

• Error #610

Error Message: The buffer is invalid.
Solution:
1. Ensure that your port speed is set to low in the modem properties
2. In your "Port Settings", check that FIFO is not set to low
3. Reinstall the dialer again
4. Else, reinstall RAS/DUN
5. You should consult your computer manufacturer if the problem persists

• Error #611

Error Message: The route is not available.
Solution:
1. Try to reboot your computer
2. Ensure that you set the right configurations for the dialer and network settings
3. Else, install the network components again
4. If you are using a LAN connection, consult your system administrator

• Error #612

Error Message: The route is not allocated.
Solution:
1. Reboot your computer
2. Ensure that you set the right configurations for the dialler and network settings

• Error #613

Error Message: Invalid compression specified.
Solution:
1. Try to reboot your computer
2. Else, add &K3 to the extra settings.
3. If this still does not solve the problem, add &K3
4. You can also try to reinstall the modem

• Error #614

Error Message: Out of buffers.
Solution:
1. Ensure that our port speed is not too low
2. Try to install your modem again

• Error #615

Error Message: The port was not found.
Solution: Try to install your modem drivers

• Error #616

Error Message: An asynchronous request is pending.
Solution:
1. Reboot your computer
2. Try to install your modem drivers again

• Error #617

Error Message: The port or device is already disconnecting
Solution:
1. Wait until your modem disconnects properly
2. If this operation is taking too long, reboot your computer

• Error #618

Error Message: The port is not open.
Solution:
1. Reboot your computer
2. Ensure that no other program is making use of the modem

• Error #619

Error Message: The port is disconnected.
Solution:
1. Reboot your computer
2. Ensure that no other program is making use of the modem

• Error #621

Error Message: Cannot open the phone book file.
Solution: Install Blue Frog connection software again

• Error #622

Error Message: Cannot load the phone book file.
Solution: Install Blue Frog connection software again

• Error #623

Error Message: Cannot find the book entry.
Solution: Install Blue Frog connection software again

• Error #626

Error Message: Cannot load a string
Solution:
1. Try to reboot your system
2. Install Blue Frog connection software again

• Error #627

Error Message: Cannot find key
Solution: Install Blue Frog connection software again

• Error #628

Error Message: The port was disconnected
Solution:
1. Install Blue Frog connection software again
2. Try to install your modem drivers again

• Error #629

Error Message: The port was disconnected by the remote machine.
Solution:
1. Install Blue Frog connection software again
2. Try to enter an alternate Access Number
3. Try to install your modem drivers again

• Error #630

Error Message: The port was disconnected due to hardware failure.
Solution:
1. Install Blue Frog connection software again
2. Try to reinstall your modem drivers
3. Try to use an alternate modem
4. Else, replace your current modem with a new one

• Error #631

Error Message: The port was disconnected by the user.
Solution:
1. Ensure that the right Access Number is being dialled
2. Try to reboot your computer

• Error #632

Error Message: The structure size is incorrect.
Solution:
1. Try to reboot your computer
2. Install Blue Frog connection software again

• Error #633

Error Message: The port is already in use or is not configured for Remote Access dialout.
Solution:
1. Try to reboot your computer
2. Else, try to reinstall your modem drivers

• Error #634

Error Message: Cannot register your computer on the remote network.
Solution:
1. Try to check your network settings and modify your computer name
2. Install the network control panel again

• Error #635

Error Message: Unknown Error
Solution:
1. Try to reboot your computer
2. Install Blue Frog connection software again
3. Else try to reinstall your modem drivers

• Error #636

Error Message: The wrong device is attached to the port
Solution: Check in your settings if you have chosen the right modem

• Error #637

Error Message: The string could not be converted
Solution:
1. Try to reboot your computer
2. Install Blue Frog connection software again

• Error #638

Error Message: The request has timed out.
Solution:
1. Try to reboot your computer
2. Install Blue Frog connection software again

• Error #645

Error Message: Internal authentication error.
Solution:
1. Try to reboot your computer
2. Install Blue Frog connection software again
3. Else, try to reinstall your modem drivers

• Error #650

Error Message: The Remote Access server is not responding.
Solution:
1. Check that your connection and network settings have correctly been configured
2. Ensure that the modem has been correctly set up and look for updated drivers
3. Set FIFO buffers to a lower speed and ensure that you have unchecked the option "Only connect at this speed"

• Error #676

Error Message: The line is busy
Solution: Ensure that your Access Number is still active and is correctly dialled

• Error #678

Error Message: There is no answer.
Solution:
1. First of all check that your phone lines are correctly plugged in
2. Ensure that the Access Number is correct
3. Else, try another Access number
4. If you are trying to make use of your connection in a bad weather, this might be the source of the problem. Wait until it calms down and try again
5. Else, install your modem drivers again
6. If the problem persists, you might need to contact your ISP

• Error #680

Error Message: There is no dial tone.
Solution:
1. First of all check that your phone lines are correctly plugged in
2. The cables might be damaged. Replace them and try again
3. Else, install your modem drivers again
4. If the problem persists, you might need to contact your ISP or a technician

• Error #691

Error Message: Access denied because username and/or password is invalid on the domain.
Solution:
1. Ensure that you have entered the right username and password
2. Make sure that your account is active and turned on
3. You might also try to enter another Access Number
4. If the problem persists, you might need to contact your ISP

• Error #692

Error Message: Hardware failure in port or attached device.
Solution:
1. Browse for and remove any Blue Frog init strings
2. Install Blue Frog connection software again
3. Else, install your modem drivers again

• Error #718

Error Message: PPP Timeout
Solution:
1. Try to reboot your computer
2. Ensure that you have entered the right username and password
3. You might try another Access Number
4. Install Blue Frog connection software again
5. Else, install your modem drivers again

• Error #721

Error Message: Remote PPP peer is not responding.
Solution: For Windows 2000/XP/Vista operating systems, ensure that the security setting for the dialler reads "Allow unsecured Password"

• Error #734

Error Message: The PPP link control protocol terminated.
Solution: For Windows 2000/XP/Vista operating systems, ensure that the security setting for the dialer reads "Allow unsecured Password"

• Error #777

Error Message: The connection attempt failed because the modem on the remote computer is out of order.
Solution:
1. Install Blue Frog connection software again
2. Install your modem drivers again
3. Else, install a new modem

• Error #778

Error Message: It was not possible to verify the identity of the server.
Solution:
1. Ensure that you are dialling the correct phone number
2. Verify the connection and Network settings
3. Ensure that you do not have an outage on the phone line
4. Ensure that you have correctly installed your modem and check for updated drivers
5. Set FIFO buffers to a lower speed and ensure that you have unchecked the option "Only connect at this speed"

• Error #779

Error Message: To dial out using this connection, you must use a smart card.
Solution:
1. Ensure that all authorisation is allowed in your connection settings in the Security section
2. Verify that you have correctly set the other dialler settings
3. Else, create the dialler again
4. You might need to use the Smart Card Reader as initially setup by the Network Administrator

• Error #780

Error Message: An attempted function is not valid for this connection.
Solution: Ensure that the dialler, not the one set up for LAN use though, has been properly installed and has the right settings

• Error #781

Error Message: The encryption attempt failed because no valid certificate was found.
Solution: You have to get a valid certificate by registering to the website http://windows.microsoft.com/...

Note: The solution for the following problems is already provided in the error messages. If you are still facing problems with them, either contact your ISP or a technician to fix the problem.

• Error #782

Error Message: Network Address Translation (NAT) is currently installed as a routing protocol, and must be removed before enabling Internet Connection Sharing

• Error #783

Error Message: Internet Connection Sharing cannot be enabled. The LAN connection selected as the private network is either not present, or is disconnected from the network. Please ensure that the LAN adapter is connected before enabling Internet Connection Sharing.

• Error #784

Error Message: You cannot dial using this connection at logon time, because it is configured to use a user name different than the one on the smart card. If you want to use it at logon time, you must configure it to use the user name on the smart card.

• Error #785

Error Message: You cannot dial using this connection at logon time, because it is not configured to use a smart card. If you want to use it at logon time, you must edit the properties of this connection so that it uses a smart card.

• Error #786

Error Message: The L2TP connection attempt failed because there is no valid machine certificate on your computer for security authentication.

• Error #787

Error Message: The L2TP connection attempt failed because the security layer could not authenticate the remote computer.

• Error #788

Error Message: The L2TP connection attempt failed because the security layer could not negotiate compatible parameters with the remote computer.

• Error #789

Error Message: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

• Error #790

Error Message: The L2TP connection attempt failed because certificate validation on the remote computer failed.

• Error #791

Error Message: The L2TP connection attempt failed because security policy for the connection was not found.

• Error #792

Error Message: The L2TP connection attempt failed because security negotiation timed out.

• Error #793

Error Message: The L2TP connection attempt failed because an error occurred while negotiating security.

• Error #794

Error Message: The Framed Protocol RADIUS attribute for this user is not PPP.

• Error #795

Error Message: The Tunnel Type RADIUS attribute for this user is not correct.

• Error #796

Error Message: The Service Type RADIUS attribute for this user is neither Framed nor Callback Framed.

• Error #797

Error Message: A connection to the remote computer could not be established because the modem was not found or was busy.

• Error #798

Error Message: A certificate could not be found that can be used with this Extensible Authentication Protocol.

• Error #799

Error Message: Internet Connection Sharing (ICS) cannot be enabled due to an IP address conflict on the network. ICS requires the host be configured to use 192.168.0.1. Please ensure that no other client on the network is configured to use 192.168.0.1

• Error #800

Error Message: Unable to establish the VPN connection. The VPN server may be un-reachable, or security parameters may not be configured properly for this connection.
Solution:
1. Check your ADSL line as it is probably not synchronized
2. Verify that your Security Options are correctly set in your connection options
3. Either your Network Card or your modem might not work properly. Contact a technician if the problem persists

• Error #995

Error Message: Operation aborted.

• Error #1382

Error Message: Maximum length exceeded.

• Error #1793

Error Message: Account expired.

• Error #2250

Error Message: Network connection does not exist.

Missing or lost sound in Windows

Verify software volume control settings

First verify you see a small sound icon or in the Windows notification area (bottom right-hand corner of your screen). If this icon is missing, follow the steps below. If you see this icon skip to next section.

Windows XP

1. Open the Control panel
2. Open the "Sounds and Audio Devices" icon.
3. Verify the "Place volume icon in the taskbar" checkbox is checked. If this option is not available or is grayed out, skip to the next section of this document.
4. If you were able to check this box, click ok and close out of this window and the Control Panel.
5. Double-click the sound icon in the Systray and verify that all the sound volumes are mid-way or higher.

Windows 2000

1. Open the Control panel
2. Open the "Sounds and Multimedia" icon.
3. Verify the "Show volume control on the taskbar" checkbox is checked. If this option is not available or is grayed out, skip to the next section of this document.
4. If you were able to check this box, click ok and close out of this window and the Control Panel.
5. Double-click the sound icon in the Systray and verify that all the sound volumes are mid-way or higher.

Windows 95, 98, or ME

1. Open the Control panel
2. Open the "Multimedia" icon.
3. Check the checkbox for "Show volume control on the taskbar." If this section is grayed out, change the Playback "Preferred device" by clicking the down arrow and changing to an alternate selection. If that is also grayed out, skip to the next section of this document.
4. If you were able to check this box, click ok and close out of this window and the Control Panel.
5. Double-click the sound icon in the Systray and verify that all the sound volumes are mid-way or higher.

Verify the installed driver settings

1. Open the Windows Device Manager
2. Verify there are no conflicts or errors listed anywhere in Device Manager. If conflicts exist skip down to conflicts section.
3. Verify no "Other devices" are listed. If other devices are listed skip down to other devices section.
4. Verify that your "Sound, video and game controllers" category is listed, if not skip down to the missing sound card section.
5. If no conflicts or other devices are listed and your sound card is listed with no conflicts, skip to the next section.

Conflicts section

If conflicts exists with your sound card or other devices installed in your computer it is likely that either the drivers are not properly installed for that device or the sound card or other devices are conflicting. If you open the properties of the device that is conflicting and view the properties, additional details about the conflict can be found. Additional information about error codes as well as help with Device Manager can be found on our Device Manager section.

If you are unable to locate additional information about your issue or are unable to resolve the issue, follow the steps below.

1. Under Sound, Video and game controllers highlight each device and press the delete key to remove the device.
2. Reboot the computer.
3. As the computer is booting the system will detect the sound card and any of it's devices and re-install those devices. If prompted for a location of drivers, try pointing it to your sound card CD or your Windows CD. If this does not work or is unable to locate the proper files, you need to get the latest sound drivers from your sound card manufacturer.

Other devices section

If Other devices are listed, these could be the sound card or another conflicting device. If any other devices are listed it is recommended you remove those devices, reboot the computer and let Windows redetect the devices.

If this does not work, determine what device is not being detected and resolve that issue first.

Missing sound card section.

If you are missing the "Sound, video and game controllers" category in Device Manager, it is likely that the sound card drivers are not installed properly, sound card has been disabled, sound card is bad, or no sound card is available in the computer. First, verify no conflicts or other devices are present in the Device Manager; if these are present it is likely they are the sound card or devices causing the sound card not to be detected. Second, verify that the computer has a sound card and that the sound card is enabled on the computer.

If this is an on-board sound card you can verify that it is enabled in CMOS setup.

If you have no adapters or cannot click the down arrow to select the correct adapter, close out of this Window. In Control Panel double-click the System icon, click the Device Manager tab within Device Manager and ensure there are no yellow ! or red X.

If you have either of these on any of your sound devices, remove everything under Sound Video game controllers and reboot the computer. If after rebooting the computer you still have the same conflicts, double-click on the conflicting device and refer to our Device Manager error code section giving you additional information on the error code you are experiencing.

Verify speaker connections

Verify the speakers settings and speakers are not at fault by running through computer speaker troubleshooting.

Sound card drivers

If you have followed the above recommendations and you are still unable to get the sound card to work, in Device Manager remove all sound video and game controllers and reboot the computer. This should cause Windows to reinstall all missing drivers and often can correct corrupt drivers. If this does not work after rebooting the computer download and install the latest sound card drivers from the computer or sound card manufacturer. A listing of sound card drivers can be found on our sound card driver page.

Defective hardware

Finally, if all of the above recommendations do not resolve your issue it is likely that either the sound card is physically bad or that the operating system is severely corrupt. We recommend you contact the manufacturer of the sound card or computer for a replacement or additional recommendations.

 

NETWORK

                                                         

(n.) A network is a group of two or more computer systems linked together. There are many types of computer networks, including:

local-area networks (LANs) : The computers are geographically close together (that is, in the same building).

wide-area networks (WANs) : The computers are farther apart and are connected by telephone lines or radio waves.

campus-area networks (CANs): The computers are within a limited geographic area, such as a campus or military base.

metropolitan-area networks MANs): A data network designed for a town or city.

home-area networks (HANs): A network contained within a user's home that connects a person's digital devices.

In addition to these types, the following characteristics are also used to categorize different types of networks:

topology : The geometric arrangement of a computer system. Common topologies include a bus, star, and ring. See the Network topology diagrams in the Quick Reference section of Webopedia.

protocol : The protocol defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called Ethernet. Another popular LAN protocol for PCs is the IBM token-ring network .

architecture : Networks can be broadly classified as using either apeer-to-peer or client/server architecture.

Computers on a network are sometimes called nodes. Computers and devices that allocate resources for a network are called servers.

(v.) To connect two or more computers together with the ability to communicate with each other.

HARDWARE EMULATION

Hardware emulation is the use of one hardware device to mimic the function of another hardware device.
A hardware emulator is designed to simulate the workings of an entirely different hardware platform than the one it runs on. Hardware emulation is generally used to debug and verify a system under design.
An administrator must use hardware emulation if he needs to run an unsupported operating system (OS) within a virtual machine (VM). In such a scenario, the virtual machine does not have direct access to server hardware. Instead, an emulation layer directs traffic between physical and virtual hardware. This is less efficient than paravirtualization, which allows for an interface to the virtual machine that can differ somewhat from that of the underlying hardware.
Microsoft's Hyper-V includes hardware emulation because the Integration Services can only be installed on certain guest operating systems.  The hardware emulation allows the network administrator to run and interact with an embedded operating system from a desktop that couldn't normally support that operating system. (An embedded OS is a type of operating system that is created to run in dedicated hardware environments or on systems that aren't intended for interactive use.)