All the drivers that are included with Windows XP use digital signatures to verify that they have been tested by the Windows Hardware Quality Labs (WHQL). Many third-party programs are written for Windows XP must install additional drivers that have not been tested by WHQL. Therefore, they do not receive a digital signature.
Note: Some third-party vendors have tools that they can use to generate a valid digital signature even if these products were not tested by WHQL. The following procedure cannot be used to determine whether these drivers are installed.
Windows XP includes the File Signature Verification tool (Sigverif.exe). You can use this tool to find all files on your computer that are not digitally signed. For the purposes of Windows XP clean-boot troubleshooting, you have to test only the files in the %Windir%\System32\Drivers folder. Note: %Windir% and %systemroot% are variables which point to the Windows XP folder - this is normally c:\windows but may not always be, hence the variable names being used.
To use the Sigverif.exe tool, follow these steps:
Note Many video drivers are not digitally signed. The following steps may cause problems with your video resolution. These problems may prevent you from starting the computer.
The list of all signed and unsigned drivers that the Sigverif.exe tool finds is in the Sigverif.txt file in the %Windir% folder (typically, the Winnt or Windows folder). All unsigned drivers are noted as "Unsigned."
When you determine which drivers are unsigned, create a folder to move the unsigned drivers to. Typically, SysDriversBak is an easy folder name to remember. Create the folder in the Windows directory so that if the computer is put into a no-boot situation, the drivers can be restored in the Recovery Console.
Move the unsigned drivers, restart the computer (without the unsigned drivers in the Windows\System32\Drivers folder), and then test the program or other functionality to see whether the same error messages or issues still occur.
Note: Because most driver files are associated with registry entries that have not yet been changed, you may receive the following error message: At least one driver or service failed to start...
If the issue no longer occurs, the issue was caused by a third-party unsigned filter or function driver. A function driver is a driver that is used to load a specific device that uses one of the computer buses. A filter driver loads at a level above or below a function driver to add or modify the behavior of the function driver.
To determine which unsigned driver is causing the problem, use one of the following methods:
To turn off a service, follow these steps:
To disable a driver, follow these steps:
Note: Some third-party vendors have tools that they can use to generate a valid digital signature even if these products were not tested by WHQL. The following procedure cannot be used to determine whether these drivers are installed.
Windows XP includes the File Signature Verification tool (Sigverif.exe). You can use this tool to find all files on your computer that are not digitally signed. For the purposes of Windows XP clean-boot troubleshooting, you have to test only the files in the %Windir%\System32\Drivers folder. Note: %Windir% and %systemroot% are variables which point to the Windows XP folder - this is normally c:\windows but may not always be, hence the variable names being used.
To use the Sigverif.exe tool, follow these steps:
- Click Start, click Run, type sigverif in the Open box, and then click OK.
- Click Advanced, click Look for other files that are not digitally signed, click Browse, locate the Windows\System32\Drivers folder, and then click OK two times.
- Click Start.
Note Many video drivers are not digitally signed. The following steps may cause problems with your video resolution. These problems may prevent you from starting the computer.
The list of all signed and unsigned drivers that the Sigverif.exe tool finds is in the Sigverif.txt file in the %Windir% folder (typically, the Winnt or Windows folder). All unsigned drivers are noted as "Unsigned."
When you determine which drivers are unsigned, create a folder to move the unsigned drivers to. Typically, SysDriversBak is an easy folder name to remember. Create the folder in the Windows directory so that if the computer is put into a no-boot situation, the drivers can be restored in the Recovery Console.
Move the unsigned drivers, restart the computer (without the unsigned drivers in the Windows\System32\Drivers folder), and then test the program or other functionality to see whether the same error messages or issues still occur.
Note: Because most driver files are associated with registry entries that have not yet been changed, you may receive the following error message: At least one driver or service failed to start...
If the issue no longer occurs, the issue was caused by a third-party unsigned filter or function driver. A function driver is a driver that is used to load a specific device that uses one of the computer buses. A filter driver loads at a level above or below a function driver to add or modify the behavior of the function driver.
To determine which unsigned driver is causing the problem, use one of the following methods:
- Put drivers that are related to the same program or device back into the Windows\System32\Drivers folder together in the same test.
- Put the top half of the drivers back into the Windows\System32\Drivers folder in the same test.
To turn off a service, follow these steps:
- Click Start, and then click Run.
- Type %systemroot%\system32\services.msc /s, and then click OK.
- Double-click the service, click Disabled in the Startup Type list, and then click OK.
- Restart your computer.
To disable a driver, follow these steps:
- Click Start, and then click Run.
- Type %systemroot%\system32\compmgmt.msc /s, and then click OK.
- Click Device Manager.
- Double-click the device, click Do not use this device (disable) in the Device Usage list, and then click OK.
- Search for an updated driver for the device from the vendor.
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