This article was previously published under Q174567
This article has been archived. It is offered "as is" and will no longer be updated.
When you use a video card that has Accelerated Graphic Port (AGP)functionality, the only video resolution mode that works correctly isVGA mode (640x480, 16 colors). Third-party video drivers do not functionas expected, if at all. In addition, when you open a command prompt window and then maximize the screen, the screen turns black. You canpress ALT+ENTER to make the screen a window.
Support for AGP functionality is not part of the base operating system forWindows NT 3.51 or Windows NT 4.0.
AGP support has been added to Windows NT 4.0 in Service Pack 3. Obtain andinstall the latest service pack.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem has been corrected in the latest U.S. Service Pack forWindows NT version 4.0. For information on obtaining the Service Pack,query on the following word in the Microsoft Knowledge Base:
Microsoft has confirmed this to be a problem in Windows NT version 3.51A supported fix is now available, but has not been fully regression testedand should be applied only to systems experiencing this specific problem.Unless you are severely impacted by this specific problem, Microsoftrecommends that you wait for the next Service Pack that contains this fix.Contact Microsoft Technical Support for more information.