This post is bit different from the other guy who was playing WoW...
Dell Vostro 430
-8gb ram (4dim) ddr31333
-PSU: 650w cosair
- GPU:HIS HD 5850
I was barely doing anything, I was just watching youtube video and it happened to me couple of times. I updated driver to most recent one, but problem still occurs. When i play video games like Fallout NV, SC2, BFBC2, and more, it Never occured to me. So i don't know exactly the problem is.