Can anyone tell me why I can have video drivers, or a mouse that works, but not both?

Before I left for CA, I started having mouse problems, and machine lockups. I tried changing video cards, but whenever I would install the drivers for it, the mouse would stop working. I just installed a brand-new 128M NVidia card, and the mouse worked fine, until I installed the drivers. Now, it boots and the mouse won’t budge the cursor.

Any ideas?

[Update for more info]

It’s a PS-2 mouse, running on W2K. I repeat. It works fine if video drivers aren’t installed.

[Late afternoon update]

After several reboots, it’s finally working. The ways of Windows passeth understanding.