Thanks General...and n-spy for the tip.
I've tried a lot of things...cleaning out the cache, the temp files, putting back the default BIOS settings, checking all the hardware to make sure the drivers are up to date, trying different frequencies and color patterns for the monitor, testing the video card and DirectX with those animations working beautifully, loading the latest java and flash players...I really give up...
The only thing I can think of is that my monitor doesn't have a driver which is compatible with XP so XP just calls it "plug and play monitor". If that's the culprit then I think I'm gonna blow up Microsoft headquarters because I'm not going to throw out a perfectly good monitor just because they can't be bothered to make drivers that work for all the major brands.