Also err this could be a case of overheating too, I had this problem once with some other game.
My CPU was overheating and my PC was restarting every time I played it.
Though that happened when I had Vista, when I put XP back it's been fixed.
But TBH I dont think that would be the case, most likely like magix said, you should reinstall your GFX drivers (if you have the same problem when watching videos, its clear that your graphical interface cant handle anything).
Does it happen when you change the resolution to the highest on your desktop?