Please follow info from Bilbat. also just check on your MB if any of the Capicitors are swelling, they will swell on the top and have an alkilyne residue, this is caused by age and heat. if the caps are swollen it will cause a short in current within the board, it will not be able to regulate the current. by pulling the power out of the computer, the board will be able to discharge. Not sure that this is the problem but just take a quick look.