Microsoft KB Archive/314854

= How to Determine Which Video Driver Is Loading in Windows XP =

Article ID: 314854

Article Last Modified on 8/6/2002

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional Edition

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This article was previously published under Q314854



For a Microsoft Windows 2000 version of this article, see 200435.

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SUMMARY
This article describes procedures that you can follow to troubleshoot difficulties with video drivers when you start your computer in Windows XP. Specifically, the article describes how to find out which video drivers are loading.



MORE INFORMATION
If the video driver is not loading correctly, another program may have replaced some files. These symptoms point to that cause:
 * The system continues to default to VGA mode or only boots in VGA mode from the Boot menu.
 * The video driver is not loading properly.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To verify exactly which video drivers you expect your Windows operating system to load, follow these steps:  Start Registry Editor (Regedit.exe). Locate the following key in the registry:

HKEY_LOCAL_MACHINE\hardware\DeviceMap\Video

 The Device\Video0 value points to a registry key that has the location of the video driver that Windows is configured to load.

For example, the value may be:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ \Device0

 Locate the following key in the registry:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ \Device0

To see what the value setting is, double-click the InstalledDisplayDrivers value. The setting shows the driver that was loaded.

If the setting shows another registry location, a third-party driver may be being loaded when Windows starts. If, for example, Symantec pcAnywhere is installed, Device0 does not have the name of a file. Instead Device0 has another registry location, and that location gives the video driver name. For example:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\AW_HOST\Video0.

Verify the following:
 * 1) Verify that the driver file or files that are displayed in the registry key are present in the  \System32 folder, where   is the name of the folder that Windows is installed to. The relevant file or files have a .dll extension.
 * 2) Verify that the file or files are also present in the  \System32\Drivers folder. The file or files have a .sys extension.

If the links and values are not correct, or if the files that the registry key points to are not present, correct the links and values so that the system starts properly.

If the links and values are correct, and the files are present, there may be a video driver conflict. Verify that you have the latest drivers for the video adapter.

The following example shows what the registry settings are if you use an S3 video adapter:

HKEY_LOCAL_MACHINE\hardware\DeviceMap\Video

The value Device\Video0 = \REGISTRY\Machine\System\ControlSet001\Services\s3\Device0

HKEY_LOCAL_MACHINE\System\CurrentControlSet\s3\Device0

The value InstalledDisplayDrivers = s3 vga

For additional information about dealing with Video Issues, click the article number below to view the article in the Microsoft Knowledge Base:

162577 STOP: C0000143 MISSING DISPLAY_DRIVER.DLL

154754 STB PowerGraph Video VLB Display Adapter Not Detected

Keywords: kbinfo kbhardware kbdisplay KB314854

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