I installed a new video card (FireGL 5600) to correct big-time video problems with CAD software on my Dell Precision 470, but now it's worse than ever. Pixels gradually get more and more corrupt, until the machine just quits. There's no blue screen or memory dump, so I really can't give more specific information. However, I've tried every level of hardware acceleration, including "none", as well as every version of the driver (current version is 8.583.0.0, which I believe is the most recent). All to no avail. As far as I know, all drivers and the BIOS are up to date, and my registry is clean.
A likely related matter is a phantom PCI device on my system that Windows (XP SP2) does not recognize, and says has no driver installed. Device Manager says it is in Slot 1. This happens to be where my video card is physically installed (I checked - it's there), as well as where Device Manager says it is. Weirder still, the instance ID of the unknown device is:
which has the same vendor code (ATI), but is otherwise different from the ID of my actual video card. Is this the old video card ID? I think it was a FireGL 3100, but I'm not sure. Disabling/uninstalling the unknown device doesn't help (it just reappears after the next crash). Is there a DLL somewhere I need to destroy?