I have a friend who called me today saying their computer will not turn on. I checked it and sure enough, hit the power button and nothing happens. I plugged in a known good power supply that I have and still nothing happens when I hit the power button. I am now assuming that the MB is toast. Is there anything else that I can check?
Mb probably dead then. Make sure you test it after removing all expansion cards and disconnect all the IDE cables. Basically you should only have the power switch, case speaker (to hear the beeps) CPU, Video card (if no onboard video) and 1 stick of RAM in there. Also try it without a video card or RAM to see if it turns on and gives you a beep code. without RAM it should continuously beep, or it could do nothing at all depending on the board. Also look up it's jumper configuration if it's an old board that still uses jumpers.