After it's been on for awhile, if you shutdown and immediately turn back on (not reboot), does it ever shut off before completing bootup? If you're not sure, try testing. Leave it running about 30 minutes, then repeatedly shutdown and turn on. See if it ever exhibits the unwanted behavior.

Just install XP in another partition. Let's find out if this is hardware or software issue.

That's going to be great ! Nah. Keep reading suggestions...

Usually this kind of behaviour comes from either motherboard or PSU.
Even if the PSU is NOS it is still possible it has some cold start problems, so if possible switch it with another one.
Can't hurt much and easy to test.
Also make sure everything is grounded well, specifically to the back panel of the case. Had a strange boot issue a while ago with somebodies build and after touching the back of the machine I got a schock. Grounded everything by reseating the cards and after that the machine Always booted fine.
If none of this fixes it I would try it with another HDD and if that doesn't help then my guess would be a motherboard issue/feature.

clueless1 wrote:

After it's been on for awhile, if you shutdown and immediately turn back on (not reboot), does it ever shut off before completing bootup? If you're not sure, try testing. Leave it running about 30 minutes, then repeatedly shutdown and turn on. See if it ever exhibits the unwanted behavior.

Yep, got it running for awhile and then turned it off and it restarted no problem. Did this several times, so evidently it only shuts off initially after a "cold" boot. What would cause that?

Same thing is happening with a Fatal1ty FP-IN9 SLI and a OCZ Fatal1ty 750W PSU.
(with or without the case)

I just can't reproduce the problem right now ** in another front. Maybe later.

Sorry to give you wrong advice as I thought your OS was freezing or loading "forever".
It's clearly a hardware problem. I'll keep an eye on a solution over here.

Probably bad capacitors in the PSU or on the mainboard.

h-a-l-9000 wrote:

Probably bad capacitors in the PSU or on the mainboard.

Wouldn't be surprised if it was this^.

Opened it up and noticed there were (2) holes on the mobo w/o screws. Took care of one but the other doesn't line up with any back plate hole. Would this create the boot problem? The PSU was brand new when I bought it and the mobo was NOS, wouldn't think it's a capacitor issue. But in the event that's the case I'll just ride it out till it dies, this has been going on for almost a year.

It would be interesting to see if you run the system on a workbench (outside of the case) if it behaves the same.

When I first got my 486, I had a weird issue with it working fine on the bench, then not posting when I got it in the case. I convinced myself it was a grounding issue. Then I accidentally discovered the real issue, and it had nothing to do with grounding. 😊

The point being, maybe it's time to assemble it out of the case and see if the issue still occurs.

clueless1 wrote:

It would be interesting to see if you run the system on a workbench (outside of the case) if it behaves the same.

When I first got my 486, I had a weird issue with it working fine on the bench, then not posting when I got it in the case. I convinced myself it was a grounding issue. Then I accidentally discovered the real issue, and it had nothing to do with grounding. 😊

The point being, maybe it's time to assemble it out of the case and see if the issue still occurs.

Yes, when I get time that'll be the next step. Gonna have to hunt down a "power switch button/cable" to plug into the board.

May also just order another board (better quality) if only for testing purposes.

buckeye wrote:

Gonna have to hunt down a "power switch button/cable" to plug into the board.

All you need to do is touch the two power switch pins with a paper clip (or anything else conductive you might have kicking around).

Jorpho wrote:

buckeye wrote:

Gonna have to hunt down a "power switch button/cable" to plug into the board.

All you need to do is touch the two power switch pins with a paper clip (or anything else conductive you might have kicking around).

Flatbed screwdriver is also an option. I'll always have one nearby anyway 😜
And one with a plastic grip so I'll never electrocute myself and I like the firm grip it has.

Paper clips folded outward are also handy for making optical disks eject from non-powered optical drives.