Driver stopped responding, not during gameplay

Hay everyone. I thought I got rid of this twice but the error eventually came back, both times.

I have reformatted and installed drivers, don't overclock, ruled out overheating, ran memtest. I thought I got rid of the error when I set the physx configuration to the actual card. That didn't work. Then I disabled hardware acceleration on flash. The latter, which I thought was the issue, did not help. I say this because the error ONLY occurs after I play games. This does not occur during gameplay, but moments after playing, and during browsing the web. The final straw came last night when after about 10 minutes, watching on youtube, my screen started to get glitchy. That's when I ruled out hardware acceleration. It's like the video card does not adjust well when switching back over.

GTX 550ti
i5 3570k
Gigabyte GA-Z77X-D3H
Rosewill HIVE Series HIVE-650 650W psu (if it matters, I'm getting .95v from monitoring on HWmonitor)
G.SKILL Ares Series 8GB DDR3 8gb

BTW i have just been playing on steam, and no matter which game from Limbo, to Left 4 Dead 2 and Black Mesa, the error comes afterwards. I constantly check temps after playing and it's highest is mid 50s Celsius. Any help would be much appreciated.