HP/Compaq :: Video Card- Screen Has Either Been Doing A Brief Flash Or Weird Movement And Then Locks Itself Up

my computer screen has either been doing a brief flash or weird movement and then locks itself up. Everything is running but the screen, which is frozen in place (the mouse icon is also frozen). I was wondering if anyone had suggestions on how to fix this. I thought it was an overheating problem, but it's sitting at 53•C and still does it. It started doing this when I was playing WoW (only while playing), but that was 3-4 weeks ago and until now the computer worked fine.

It will also no longer restart itself; it goes through the shut down process but then basically powers off as if I just turned it off versus shutting down turned off (this laptop has distinctive sounds for both which is how I can tell). Normally I can wait a minute or two and then turn it back on and it boots up (if I try to turn it on right after it cuts off after a second). Now however, it gets to the first logo then cuts off. I have used compressed air to blow in the vents to get rid of dust if that might be a factor.