Most peculiar problem - computer spontaneously reboots!

[ReuvenNY]

About a week ago my computer started rebooting by itself in an unpredictable manner. Mostly when not attended, but from time to time while I was using it.

My first suspicion was hardware: either memory, motherboard, CPU or power supply. I verified that all worked fine. The Motherboard temperature was within normal limits as well.

To exclude any other possible hardware problems, I booted the system with a Linux distribution (Knoppix 3.9), which boots and works straight from the CD. I left it working for over 16 hours with no problem.

My next project was to check my OS. I am using Windows XP Pro. I downloaded from Symantec a Zotob worm remover. Turned out I had no Zotob. I cleaned the drive from all kinds of malware/spyware etc with Ad-Aware, Spybot - Search & Destroy and with Webroot Spy sweeper. Checked for Viruses with two anti virus applications - Avast and Trend Micro online.

I also used VCOM’s Fix-It-Utilities 6 pro to clean up the registry.
The only thing I didn’t try yet is stopping the Google Desktop Tool from indexing, but I do not think it has anything to do with this. (Correct me if I am wrong).

So now I am at a loss - short than reinstalling Windows, is there anything else I can do? Did I overlook anything? Did anyone else have a similar experience?

Thanks for any help.


My system:

Asus K8V SE Deluxe
AMD Athelon 64 3200+
1.5 Gig RAM PC3200 400MHz
1SATA 160Mb drive
1 IDE 120 Mb drive
LG Super Multi DVD RW
Sony DVD-R drive
GeForce FX5200 128Mb video controller
Floppy drive
Fax Modem
Windows XP Pro with SP2
Zone Alarm

[kev7555]

Every time I've had this happen it was hardware-related (usually power supply). It sounds like booting from the Linux disk eliminated that possibility.

[Cricket]

Turn off WinXP's "Automatically Restart" option in System Properties > Advanced > Startup and Recovery > System Failure. With this off you might be able to see if you're getting a BSOD that could help you figure out what's causing the problem.

Cricket

[Snod Blatter]

This is screaming PSU at me... even more so when he says:

Originally Posted by ReuvenNY To exclude any other possible hardware problems, I booted the system with a Linux distribution (Knoppix 3.9), which boots and works straight from the CD. I left it working for over 16 hours with no problem.

What was it doing? If it wasn't doing anything, then I would imagine that (because koppix has to run on little memory) that there are no backgrounds applications and such to work the CPU and stress the PSU...

[ReuvenNY]

I did turn off the auto reboot and did get the "blue screen of d", but the message there was not helpful.
The Knoppix indeed did not work too much, but it did check every 3 minutes my email in my Thunderbird IMAP account as well as some personal pages (MyWay and Yahoo) that refresh every few minutes.

Follow up report:

Listening to all the advise and comment here and elsewhere, I downloaded every possible adware defense program, antivirus as well as two Root Kit revealers - one from Systernals and the other F-Secure Blacklight.
Cleaning up my system was lengthy process, but did not completely resolve the problem. What apparently did it was restoring my system 10 days back. (Surprisingly I could not successfully restore it to several earlier points, even though it seemed like an option).
It’s been now over 48 hours and my machine doesn’t reboot.

[ReuvenNY]

An epilogue:

Having played with my computer further, I have identified the actual culprit - Google Desktop Search beta 2 and/or one of the plugins for the program I installed. How do I know? After the machine worked fine for almost three full days, I decided to reinstall the Desktop Search program, which immediately started indexing my files. A few hours later the machine rebooted. As soon as I uninstalled it, it now works for over 24 hrs non-stop.

I have notified Google Tech Support.