You did not mention which Dell PC you have or which Video card you are using. Don't get any video drivers from Microsoft. Go to the vendor's site directly. Your problem needs a trial & error approach, but I am guessing that it is a video driver issue. Microsoft's Direct X program can also cause your problem. Go to Microsoft and get Direct X 7.0a. What did your come with? At start-run, enter dxdiag and that will tell you which version. If you have Direct X 7.0, it is buggy and 7.0a fixes it.
Also, double check device manager for conflicts. I have experienced problems and Device Manager was showed that everything was OK. If you have PCI steering and there are resources being shared, sometimes swapping cards around so that they share different resources can solve lock up problems, especially if the video card is sharing with another device. I'd get the latest video driver first.

I have a Dimension 450 with a Voodoo3 3000 AGP card. I loaded the DirectX7.0a and updated the Voodoo driver from 3dfx. Still locked up. Support is arranging for a video card replacement next week. In the meantime, all the changes they had me make in the sytem files have really screwed things up. I spent all day on the phone with 3 different Dell Support folks to try to figure out what happened. All they said was basically - good luck.