PC power will not stay off

I have a Clone HW Win 98 pc that will not stay powered down.  After a shutdown it will power back on.  Even worse, if you hold the power button in for 10 sec it turns off and then back on.  The only way to turn it off is with the power cord.  I have checked the pwr mgt settings and also the BIOS settings to make sure the pwr state if off after power outage.  I can't seem to find that setting in this AMIBIOS.  I figure it is a short somewhere but I don't know where to start.  Any ideas?
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Maybe a hardware failure in the power supply or in the mobo ?
Try measuring the voltage on pin 14 of the ATX connector. To switch the power supply off, it has to go to +5V. If it does not do this, either the power supply or the mainboard are bad.
probaly just the switch.  Try pulling the cord off the motherboard.  See if it auto turns on you.
Marc ZCommented:
Are there any USB connections or network cables connected to this machine? If so, try disconnecting them, then shut down.
There are settings in those two items I can think of that can power up the computer again.
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Take a look at Microsoft's troubleshooting guide for Win98: http://support.microsoft.com/?kbid=238096&sd=RMVP
If it runs ok when going then its not a short because the short would make it continually reboot and never come on properly. In the bios you need to disable all the power management setting as well as wake on lan wake on ring and if there is any irq monitoring turn them all off too.
If connected via ethernet, try changing out NIC if none of the above suggestions fix the problem.  Use a different make/model of NIC.  I know it may seem strange, but have seen it happen.  NIC keeps trying to autostart regardless of BIOS settings.
1. disconnect as much hardware as you can
4. try other PWR button or disconnect powerbutton and put screwdriver to the PWR-button connector on motherboard
3. try other PSU
4. try other PWR button
5. try a live-CD of a linux-flavo and choose shutdown. what happens?
6. install win98 t another HDD ... still same problem?
From past experience it is a very common Win98 problem. Your shutdown problem can be resolved with the proper udates from Microsoft. Since Win98 past its life cycle with Microshaft ouyu may want to look up on Google for the patches and fixes: search string: win98 shutdown patch     That should bring you what you need to fix your problem.

Don't know if this helps but;

I had a similiar problem on a windows ME machine a few years ago.(also happend after upgrading to XP)

It started happening all of a sudden, the only way to keep it off was the switch in the back.

It turned out to be the motherboard since I eventually replaced it becuase it had too many blown/leaking capacitors.  I replaced it with the same make/model and everything worked fine.

But the problem I had would only happen about 90% of the time, on a rare occassion it would stay off.
MarkWThompsonAuthor Commented:
Hello!  Wow, thanks for the many fast responses.  Most of these options I already tried before I posted but the one thing I could not do for lack of spare hardware was replace the power supply.  I found a spare one hidden away and voila, it works!  So the winner is......NetTechDude.  Oh and Dually681, thanks for the reminder.  Now I remembered from years ago some problems I worked on that were similar.  This may be helpful to me in the future.  Thanks Guys and Gals!!!!

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