MY friend just got a Pentuim D 820, that came with a pci-express mobo. He has a nice 450 wattt psu, and a good case. Everything is connected correctly and the psu is in working order. There was a problem with connecting the heatsink to the cpu because it would start up, run for a few seconds, and shut down. We removed the heatsink, re-applied arctic silver put the heatisink back on and it now runs full time, the cpu kept overheating and shutting down. Thank god for the mobos sensors, it didn't fry the cpu. The computer will stay on but there is a problem with it not displaying anything. We've tried my X800 and an old pci graphics card and nothing will give an image to the screen. The hard drive turns on, everything works, it's just that nothing comes onto the screen. What could this be, we're reeally scrambling for ideas, please help.