this is probably a good time to ask this:

my desktop refuses to run Linux. It's a stock Dell of some sort from late 2006/early 2007. After an hour or two of moderate use, sometimes much less, the mouse locks up and a few minutes later the computer locks up totally. It seems like there might be a CPU spike before the stall (even if doing something that should need very little CPU cycles, like loading a webpage). CPU doesn't seem to overheat. I've replaced or removed pretty much everything: the RAM, the DVD drive, the mouse, the wireless modem, the graphics card, the monitors, so it doesn't seem to be related to any of those. Haven't replaced the HDD or the keyboard. Happens with several different linux distros, in particular with ubuntu and mandriva. The computer works virtually flawlessly with Windows XP.

Any ideas what the problem could be? I can give more info if it would help.

try SuSE.

Its amazing.

I have not yet tried SUSE/openSUSE/related stuff, I think, will probably give it a go. Any reason why it should work when other OSes haven't?

when you changed graphics cards did you change chipsets ie from geforce to radeon? if the cards were related the same driver issue could easily cause that.

Based on your crash symptoms with some wild and crazy ideas mixed in:

Your bios plug and play options are not configured properly(off?)
Your bios plug and play is buggy (old version of bios?)

or some Linux driver doesn't like the way plug and play interupts are assigned.

GL... A tough one.

Also try one of those CDROM RAMdisk boot linux versions. Just for debug purposes.

flashing the bios is always a fun way to spend a half hour and with a machine of that vintage could even involve a floppy disk!

How about the service tag?

In the windows world, the sort of problem you describe would always be a driver issue. I'd want to strip the machine down to the minimum of components: video card, keyboard, mouse. Then run a clean install (like a live CD). Use the generic VGA video driver. The goal would be to find a configuration that works. Then add components / drivers one at a time, testing each step to see if it is still working. Debugging from working -> not working is much better than debugging from not working -> working. This assumes that you can test it somewhat reliably. If you can't, then you'll need some better tools, like a kernel mode debugger or something, to examine the state of things when it freezes. I don't know what the Linux tools for that are called, but I'm sure they exist.

and for random psychic debugging, disable all power management stuff in BIOS.

or for all that effort you could buy a new box for $300 and install Ubuntu on that

Run a memory test.

Well I had a laptop with an integrated graphics card (An ATi mobility 200m, I believe). I tried 3 distros (redhat, Mandrake/Mandriva, Ubuntu), and none of them had a decent integrated driver for that card. I've used SuSE ever since and the driver support has been pretty damn good.

Its also still surprisingly good despite being bought out by Novell. If you want an alternative OS, though, try Ubuntu. Its pretty good as well.

This sounds most likely to me

As old school as it may be, IRQs can actually be relevant in Linux still.

Also Roundtower - just for ***** and giggles, check your capacitors on your motherboard. Its an outside shot, bu you certainly shouldn't overlook it as a possibility.

(If you don't know what that means, just open your case and look at the little metal cylinders. If any of them look puffed out at the top, your mobo is going bad)

thanks for all the suggestions, I'll have another go at it tomorrow

some of the things I already tried, some I haven't looked at yet:
memtest - passed repeatedly, also I've tried it with different RAM
graphics card - haven't tried a different one, but it still fails using the integrated graphics
running from a CD - done, same symptoms. actually I did this before installing to the hard drive (the standard ubuntu install CD can do this), and figured screw it, I'll be able to fix it better once I install it
removing everything - haven't tried it without the hard drive, if that was one of the things Chips is suggesting, but I've removed or replaced practically everything else. same symptoms, though, when run from a live CD
testing it reliably - not really, it usually takes a while to fail each time, if I had a tool that told me exactly what was going wrong that would be a big start!
bulging/split capacitors - the motherboard looks visually OK
service tag - will put it up later when I'm there
messing with the BIOS/trying yet another distro - not done yet, that is probably my next port of call.
buying another computer - also an option

Either that's changing or different in Euroland. Most job descriptions in the field ask for Adobe skills here.

+1 on this, burn a memtest CD and let it run for a night. Symptom kind of looks like some bad RAM. Could also be a bad HDD
Edit: I see you did the memtest already

Checking
/var/log (probably /var/log/messages) for IRQ stuff would be a good start imo. What's the current distribution you have installed? Scribble down the time next time you successfully crash the system and you should find something in the logs (asking for the distribution due to the different locations of logfiles etc. pp)

I had problems with my laptop getting it to run Ubuntu. One of the updates killed it and I couldn't install it again. Solution: use a different distribution.

last laptop I installed Ubuntu on would not take wifi no matter what I did. useless.

You probably had a wireless card with no open source drivers. If you want to run Linux you need to be like Apple and get dedicated hardware first (even more true for stuff like Open BSD). These days most stuff works reasonably well but if you assemble your machine with Linux in mind I belive it actually is the best operating system out there for the desktop unless you need specific software (i.e. poker, video editiong) etc.

Last laptop I had, Mac OS X didn't even install on ergo Linux > OS X
Second to last one Windows didn't install on ergo Linux > Windows
tl;dr Linux > all :P

Since I need Windows for work I can't get rid of it but I think it has gotten reasonably useable/better over time (currently running Windows 7)

driver was fine, the distro had some known issue wrt wifi

Be careful what you ask for!

http://www.av8n.com/computer/htm/kernel-lockup.htm

That link describes how to tackle your class of problem and get the equivalent of a windows BSOD out the serial port. It's not super easy.

Cena squats. Nice form imo, deep squat, heavy weight.

Hey guys

Happy 30k

I'll open the Pub after a few people get really angry at me

LOL wp wp

dude you ruined it by posting here, we could have had a ****ing meltdown, would have been awesome!

grats