So for about a week or two now i have been experiencing this glitches that seem to come around after the computer has been on for more than 2 or 3 hours. I have noticed restarting the machine will get rid of them. I have a 2.4ghz MacBook with 2 gigs or ram from early 2008. I am running Snow Leopard 10.6.2 Does anyone know how to fix this? I think it might be a messed up graphics card, but i don't have much of a clue. I have noticed when trying to take a selected screen shot over the dock the glitches will go away, but they only happen on the dock, wallpaper, and window shadows, they are also random every time.