Problem with CPU

So when 8pin cpu plug is plugged in, comp will start then off within seconds...repeatedly.

Take cpu plug out, everything starts and stays on, can sometimes shimmy plug in and it stay on but once try to restart the same happens..

I've reseated everything i can think of, theres no visible damage(bulging or leaking capacitors, no burns or bent or broken pins or pieces). Unplugged it all held power button 30 sec. replaced power supply, blew dust out, took off cpu fan clip and replaced, took memory out and replaced, basically idk why it's doing it and anything I've found so far (been messing with it for the last 8-10 hours going out of my mind) doesnt work for me. Can anyone help?