As I said before, I found the Omega Drivers very stable. But this morning, I did a Windows Update and found that it crapped out. A simple reinstall fixed it.
After some googling (and much cursing Micro$oft), it seems that Windows Update replaced my working driver with a broken (or incompatible) one. I have an ATI card with XP, while the post below has an NVIDIA card with Vista. Seems likely, though….
EDIT: I made a mistake here — it was actually a SATA controller thingy, not a video card.
So I’d recommend keeping the installer package for a working driver nearby when you update. And it’s a very bad idea to let Windows automatically install for you — for example, if you have your school essay open and unsaved, go to the bathroom and come back, you may find it gone.