What would cause this? (computer problem) Sometimes when I'm playing games, or even just browsing the web, my screen will get screwed up into a sort of a colored pixel checkerboard. It freezes everything if I'm in a game, no sound or anything continues, but the computer stays on. I have to power it down and wait a while then power it back on again. Sometimes, it doesn't even boot on the first few tries. I'm assuming it's a CPU problem, yet most of the time it works perfectly, and it's not overclocked or anything. Anything I should look into to fix it?