My Mac G4 quicksilver will not power on. I tried the cmd option P R keystroke, pressing the reset button, leaving the system unplugged for a while, and replacing the clock battery. Power cable and outlet are fine. The next step is to replace the power supply. I want to use a PC ATX power supply that I have on hand, but the power slot is different. The mac motherboard has two extra holes for the main connector. Is there some way I can adapt it?