Alright, I got a new motherboard (Asus A7V266-E) and processor (Athlon XP 1700+).
I installed them both, got the bios up, got Linux up (I run a dual-boot system), but Windows XP Professional won't start.
It does that little text progress bar thing at the bottom and them dumps me to a blue screen that says
"A problem has been detected and windows has been shut down to prevent damage to your PC."
and says that it could be the result of a boot sector virus, or a hardware upgrade etc. Then it gives a bunch of error codes - 0x0000007b (and others that I didn't bother to copy down).

So, anyone know how I can get this working?

argh. nobody wants to reply to posts. grrrrr. either way, as far as i know, windows xp should work ok in a dual boot environment. depending on what you start boot as, it may be an obscure incompatibility in either xp or linux. try another distro mebbe.

first though... try using the xp cd to test stuff... you can redo your MBR and other stuff that may cure the problem... I know I installed a linux distro once and it just took over my MBR and I couldn't boot XP at all anymore... I was able to redo the MBR with the recovery cd and boot xp and change shtuff... worked for me...

It's not the dual-boot that's the problem, it's stupid XP not being willing to move over to different hardware.

I'm pretty sure, anyhow. It's booted fine with LILO for months, it wasn't until I tried to move the hard drive over to this new motherboard that I had any troubles.