I have a seeming power supply or motherboard problem with my old IBM Netvista machine running Windows 2000 SP4. Sometimes I try to TURN it on, and it doesn't turn on at all. There is no spark of life when I press the power button. Sometimes when the computer does turns on, it does not boot up (no BIOS screen, no MONITOR signal at all). The only thing that runs is the fan. I heard something spin once, either the HD or CD-ROM drive, but that's it.

Sometimes with the computer running, but not booting up, holding the power button to turn off the machine will prove unresponsive. I will UNPLUG the computer, it will turn off, then plug it back it and it will automatically turn on and run the fan only again.

Sometimes the power button does turn off the machine after pressing and holding the button for 5 to 20 minutes. Then I will turn the computer on again and it will boot NORMALLY. I've already taken the machine apart, and find no obvious problems with the power button connections, motherboard, or power supply. What is the problem here?

Thanks for any help.The best way I can think of to get to the bottom of the problem would be to test the pc with a different power supply, if you have one.

Alternativly you could try testing the PSU by shorting two of the connecting pins together to attempt a manual start (of the PSU only, not the whole PC). Instructions can be found at: http://www.duxcw.com/faq/ps/ps4.htm

As the website sais though AT YOUR OWN RISK! And this method will only prove that the Power supply is starting correctly.

If the PSU is ok then you could have a more serious problem i.e motherboard or bios fault.Unfortunately I don't have another power supply. I've been looking into bios and motherboard faults, and I'm going to chance that maybe a low motherboard battery may be the issue, since before this problem, I noticed that the system clock in Windows would lose track of the time. Sometimes the only way to get the computer to turn on would be to poke the motherboard itself, so I don't know if that may be the problem.