i am working on a compaq desktop, and cannot get it to turn on. When i plug the power cord in, the fans turn and i have a green power light for around 1 second. Then the fans quiet, and the power led flashes red. I can hit the power button, and the fans will turn for a second, then quiet again. The flashing red light never stops. WHat could cause this. Customer said it would turn on before they brought it in. Any ideas?