PC won't turn on after replacing CPU cooler

Siducky

Prominent
Jun 25, 2017
1
0
510
I took my PC apart and took out the motherboard to fit a new fan into my computer. The motherboards pins for the CPU seem okay but 2-3 pins which are a little bent/misplaced. I have put my computer back together and it will not "boot". There is no signal to the monitor? I have refitted the GPU. What else could it be?

Edit: When I turn it on the PC goes to turn on but switches itself off and restarts without showing anything on screen? all the lights and fans seem to be working and the CPU feels warm.