Windows XP SP 2 using WMP 11 to watch a DVD, or a video clip the movie will
play for 30 seconds or so and then the screen goes blank. The audio
continues, but I'm staring at a slightly grey screen. No other way to stop
it other than to turn the computer off. Any thoughts or suggestions?

Also, tried to use CyberLink Power DVD to view the DVD, same thing. After a
brief viewing, the screen goes blank, but the audio continues.

Quicktime video files work fine, FLV files work fine.