Hrmmmm.... try this

Reboot. RIGHT when it says Starting windows 98 or whatever. Hit F8. If you have to just wack the shit out of F8 from the moment you turn the computer on. Really shouldnt be needed though.

From the menu choose Safe mode.

When it gets done booting up and warning you you are in Safe mode (no shit). Go to Start-Settings-Control Panel. Double click network.

In there you should see Client for microsoft Windows. Double click that. Uncheck the box that says log on to Windows NT Domain.

Reboot in regular mode. I hoppe that takes care of it.