Have you found any more info on what might be causing it? My comp does the same thing. Only in games, CSS and Warhammer are the two I have had it happen during.
My drivers are all updated, and the comp is only 4-5 months old. Using HD 4870, but my friend has the same problem, or similar, on a Nvidia card. Haven't messeda round much buts it gets really annoying some times.
