I'm having the same problem with an asus 5770 with windows 7 64 bit.
p55 ud4p mother board
700 watt silent pro
4gig gskill memory
I've looked up a few things, some people are saying memory, some say drivers, I didn't completely understand the fix but someone said it was being cause by the core clock dropping too low in 2d mode.
I'm trying to decide if I should rma this one myself. but I really feel like it's a driver issue since it didn't happen during the 30 min i was running dual monitors.
Has anyone heard if the 58xx cards are having the same issue?