OutbreaK 0 Light Poster

My computer has been randomly crashing at times, and I can't figure out why. It would display numbers quickly on a blue screen and fade out. I did a system restore and it booted me back to SP1 because that what came with my computer. If i ran HJT and other things could you possibly tell me why and what to do? A lot of my programs won't start and when i drag a window accross the screen it goes in sliding phases instead of a smoothe drag like before. Thanks.