I'd check out the Error Log, figure out what else was running at the time, and see if there's a conflict. I'd make certain to disable any HP programs that might be running as well as Folding@Home.
I haven't had a problem with my video card (same as yours including Forceware drivers) besides a few freak incidents. I don't know if using an older driver would help.
<No way you can read this. My handwriting's illegible>