motherboard, CPU/HSF, PS and speaker. No beeps, and you've got those 4 to swap out. My guess would be a bad board.
Running XP-PRO,500MHZ,512MB,Okia switching Power supply(420ATX-420W Max)and Intel MotherBoard.Whenever i turn on the PC, it powers on for about 3 seconds and shut off, then the only way to try power up again is by unpluging the power cord, then plug it back in, press power and it does the same thing. I remove the cover of the pc and press power to see exactly what is physically powering on and i notice that the power supply fan, CPU FAN and a third internal fan turns on. I strip the fan down of almost all items that draw current an the problem still remains.
Anyone cares to wade in on my problem and share your expertise with me.. Thank you...PS: I even tried a magnifying glass and still could not find the model number anywhere. I did see intel MB written in bold letters. System is about 5 years old Pentium 3 processor.