I just built my first pc. It's been running fine for 3 weeks. Temps stayed low. Today I sat down at my desk and my keyboard cord was tight. I unplugged it to un tangle it and the power strip came out of the wall. I plugged the power strip back in and now my pc has no power. I've checked 3 different outlets and the switch on the back of the power supply. No power at all. I also opened it back up and unplugged the 20+4 pin connector from the motherboard and reconnected it. Nothing....Please someone tell me whats wrong