Immediate shutdown/reboot
 

First off, this looks to me like a hardware problem, but I'm gonna ask anyway to see if anyone has some pointers for me. My problem is that my computer (running Gentoo GNU/Linux 1.4, with Linux 2.6.4-rc1) keeps randomly rebooting seemingly without a reason. The screen just goes blank for a second, and then the BIOS-information pops up. I have ran this computer with basically the same setup for a long time without experiencing anything like this. Infact, it was even used as a server with several months of uptime for a while.

My first thought was that the problem must lie within the kernel, so I tried stripping out my .config of any unnecessary drivers etc, so I only had the things necessary to boot the computer. The problem still remained, so I downgraded to Linux 2.6.0, which has been run on this very computer for 5-6 days without a reboot. The computer still insists on rebooting itself in the same way as before, so now the clues point me to user space. 'ps aux' tells me nothing unusual. (Except for "[netstat] <defunct>", which I don't recognize. Has anyone got a clue what this is?). The only thing that shows up in syslog is "syslogd 1.4.1: restart." after the reboot has occurred.

The next thing to try is to run a Damn Small Linux-CD to see if it keeps doing this. If it does, I suppose I'll have to look for hardware-issues. In case you too think it's the hardware that does this to me, could you please point me to any particular device which might be responsible? Thanks in advance, for any help I might get.

edit: I have also checked CRON for any malicious scripts/programs etc, but found nothing. The reboots happen at random times too, so I don't think that an automated script is responsible.

Possibly a poorly-seated component is coming loose? Have you checked your temperatures, maybe its overheating?

It seems like this has not always done this, do you have the original kernel you were using lying around somewhere? You might be compiling kernels with flakey power management options turned on.

I really made sure that no power management was included in the kernel, and since I compile kernels about five times per week, I don't think I missed anything. The temperature shouldn't be the bad guy, since I even removed the wall to the chassi and run the computer with an open window nearby.

Could this happen because some PCI-card is slipping out of it's socket? I do have some components not screwed tight, because I have a habit of changing NICs and sound cards as it suits me. Perhaps I'll check those cards out.

Thanks for your help. I really appreciate it.

A failing power switch or power source is a possibility.

That could be true. I had it connected to several branching power switches and such, but I removed it all and plugged it directly into the wall to make sure that it wasn't an electrical problem. If it is, however, the problem must lie either inside the wall somewhere, or in the power source of the chassi (don't know what the term is in english).