This is very strange. Ok so I have a computer that will not boot with a 8600 gts video card but it will boot with a 6600 gt. But the 8600 gts does work in another computer. I couldn't figure out why this computer wouldn't boot. So I bought another motherboard, psu, cpu, and still nothing. But for some strange reason it boots with an older video card. It doesn't make sense right? I've tested it with just the cpu, ram, video card and still nothing. Also this computer has a usb over-current problem so I have to unplug that from the mother board. I really don't know what else to do. I was thinking of getting another case but I'm not sure if that will do anything.