Usually, I've found lock-ups related to bad or wrong memory. You Debian distro should have an option for testing memory (at pre-install), My Mandriva does anyway. If Memory checks out ok, try the Video card memory.

If it ran good under Windows before, that's 'cause Linux utilizes more of memory, more often (to speed things up)

Its up now and I'm testing out disabling some of the power options, sleep, and idle and things like that. If it crashes again, I'll have a look at the memory. Thanks for the heads up, you've been a life saver today!

Well, it's still rocking. I have to say, I'm impressed already! Usually I wake up in the morning to 4-5 ghost logins and a bunch of zone crash errors. Looking at it now, the logs are clean and accurate and there's nobody online, more what I expect to see at 5am :)

I'm feeling confident now that there's very little work i'll need to do on the machine itself to keep it running, and with SQL Admin, query browser, and George's tools I'm all set.

No lockups since I swapped the memory out :) It's running great.