So I was having a problem closing the door on the MDD it sounded like a fan was catching. Come to find out the fan I put on the GPU was no good and one of the blades snapped off causing extremely loud noice. It also managed to loosen the Heatsink from the card. To fix this i removed the fan and the heatsink, scraped off all the old (Yellow?) thermal paste and applied new. Put the heatsink back on, connected a NEW fan to the heatsink, provided power to the fan than booted it up. It booted fine than locked up. I turned it off and back on now it refuses to boot. It will show the APPLE logo than the spinner will show up than the apple logo changes to a "NO" Symbol. I have tried multible things I did the ALT boot option i pressed the reset button nothing. What is going on? P.S. Before replacing the fan, I would switch the power strip on and within 5 seconds of turning on the power strip, the MDD would just turn itself on. This seems to have stopped with the PMU Reset but what the hell is going on here?