Jamie

Problem has been noticably worse today (I've actually worked on the machine a
good 8-10 hours today). Machine has locked up four times.

I run memory diagnostics from Vista. It reported no issues. Might run
memtest86 over night just to be sure.

Ran chkdsk on primary system drive (WD Raptor 150) on the advice of R.
McCarty. It reported no errors. Will also run SpinRight this weekend just
to rule out anything physical with the drive.

Drive, memory, and SATA controller are all new (< 3 months old). All were
upgraded just for Vista. Used memory in with XP and WD Raptor 74 flawlessly
for several months leading up to the Vista install (clean). Don't really
expect the Raptor 150 to introduce any new caveats. Never tried SATA
controller with XP, so it is a new variable in the mix.

I'm going to look around locally this weekend for a different SATA
controller that is compatible with Vista. Will also uninstall Norton just to
rule it out.

Can't have this thing locking up 3-4 times a day.

Thanks to everyone for your suggestions.