CPU not booting up

Hello,
I have a core2 duo cpu. It worked perfectly fine until I unscrewed the cooler above the processor. The screws were of some type of plastic-metal they were misplaced and I used simple nut and bolts to fix the cooler. After which when I started my pc the cpu showed no response on the monitor . The power was okay as the fans worked fine. The processor was fine too. The screws which I fitted also touch the base of the motherboard. What should I do?