Solved: Shutdown shortly after boot

At first I was convinced this was a simple overheating issue but am no longer quite so convinced. Opinions?

I have a home-built system, don't have all the exact specs:

ECS motherboard w/Nvidia chipset
AMD Athlon 64 x2 Dual Core Processor 4800+
Nvidia G72 Video Card w/256 MB
2 GB RAM
380W RaidMax power supply
XP Pro SP3 on PATA 80G C drive
Secondary SATA 500G storage D drive

Only a few seconds after booting the system just shut down cold. Screen goes blank, all power shuts down except for that little green LED next to the LAN port. Classic overheating behavior, right?

I opened up the case and blew out all the dust bunnies. There was quite a dust build-up so I figured that must have been the culprit. I blew all the dust out of the power supply. I also made sure all the dust was evacuated from the CPU heat sink & fan. I even removed the heat sink and reapplied new thermal compound. The inside of the case was basically dust-free. But strangely, it didn't help. After rebooting it was still doing the same thing except it took maybe an extra 2 minutes before shutting down.

I swapped out the power supply with a salvaged 300W. No change.

According to the BIOS the CPU's temperature is only hitting 104F.

But strangely enough I am able to boot and keep running in Safe Mode. The minute I try and reboot in normal mode it won't even make it through the boot cycle before crashing. It runs fine in Safe Mode. The only change in configuration is that my secondary HD isn't powered. The old PS doesn't have a SATA plug. All fans appear to be operating normally.

So I put the original power supply back and reconnected the secondary HD.

Suspecting that it was a software problem I reformatted the boot drive and did a complete reinstall of XP (Service Pack 2). No luck. Still behaving the same.

Why would it crash as if it were overheating when booting normally, yet remain stable under Safe Mode? What have I overlooked?

Any opinions would be greatly appreciated.

 

Hi and welcome.

This part of your post concerns me:

The only change in configuration is that my secondary HD isn't powered.


Be sure that it's disconnected for all tests.

 

Try unplugging that second HD, and plugging it into a difference sata port on your motherboard. I had problems with boot up with my hard drive, though might have to RMA. Plugged it into different sata port and I am typing this repsonse to you now.

 

I ended up replacing the motherboard and CPU so problem solved! Here's what led up to it.

Still suspecting a heat issue I booted up in Safe Mode to see if it still might shut down if I left it running long enough and, sure enough, it did. I left it alone for about an hour. I re-booted in Safe Mode with the temperature alarm turned on in BIOS. After 15-20 minutes the alarm sounded. So there it is. It was overheating.

I'm guessing that it stayed running longer in Safe Mode because the computer runs fewer processes in Safe Mode and the CPU wasn't having to work as hard and therefore took longer to reach critical temperature.

I decided to do a more meticulous re-cleaning of all the parts. I took apart the entire rig, piece-by-piece, and carelessly bent a whole bunch of pins on the CPU. It looked like trying straighten out 2-3 dozen teeny, tiny pins was more than I could handle so decided to just replace the mobo & CPU altogether.

I bought a new board & chip, a slight upgrade to the previous one. It now runs better than before.

Thanks for your time.