I'm going to SCHOOL for IT. One project was to remove CPU check on cooling & CPU manufacturer. When I replaced it, the computer would not boot. Fans and lights worked but hit power on nothing no beeps no any thing. Hi

First U Chek the SMPS. If its working are not if its ok then remove the processor and put back its PLACE. Observe the connections if cpu fan is rotate cheking for hdd cables.
do this alla oprations.

Are you sure that you have the power switch lead on the right header?

Do you have the moterboard manual?

What is the model of the board?Were you rough at all taking it off?

eg tools SLIP, ect?

Unfortunately, some boards don't like you taking off and reapplying the heatsink and fan more than a few times.what no no and no noob's? Take the cpu back out there what you call zif zero insertion force. Meaning that there is little force needed to put it in. Its possible that there is a pin bent and or BROKE check for that I have had alot of problems with people doing that and it ened up like this.