Yesterday I was replacing my cpu fan with my Dad. The old fan was really cheap and one of the screws seemed to have slightly melted and the fan became stuck in the motherboard. After alot force (hammering and prying), we managed to get it out. However, on the back side of the motherboard (opposite of the cpu) there light scratches. Although they are very minor i can see copper coloring. After installing the new fan and putting everything together, I click the on button on my pc. I see SOME of the lights flicker and all 6 fans for half a second then everything turns off. Im not sure if I installed something wrong but im 99% sure everything is plugged correctly and it still will not turn on. (ALSO, I may have dropped the cpu and gotton some thermal paste on the back. But i cleaned it off. Not sure if that could keep the pc from running.