PC on standby?

I have a Acer PC, that has gone into standby. It was on initialy with the proc fan not connected. This turned the pc into standby. I chacked the processor, and it looks fine. But i cannot get the pc out of standby. The on button remains flashing. Any advice. I have already taken battery out and put back in. I took all power lead off and put back in. I have also taken processor out and put back in. Any other suggestions.