Two more things it isnt-
DirectX- Downloaded and installed (or reinstalled I should say) DX 8.1 from Microsoft.com. Locked up still.
Sound card IRQ- Moved the sound card to a different PCI slot, it is no longer on the same IRQ as the USB controller. Locked up still.
Oh, Aurelius, yes. I have tried the 7.78s (which cause insane stuttering on my system and it stills locks up), 12.41 (which runs the best on my system, no stutters at all, but it still locks up, 21.81 (I think) with these I get little quarter to half second lockups every couple minutes, and it still locks up, and 23. something (whatever the latest drivers are), which do little lockups like the 21's do and yes, still lock up.
I think I've utterly and completely eliminated video card drivers as the source of the lockup.