Just typing that doesn't let anyone know what the problem is and, therefore, how to fix it. So, answer these:
- When did it first happen?
- What programs do you have on your computer (i.e. web browser, virus protection)
- What were you doing when it happened?
- Is this still happening now, or did it only happen once?
Also, any other information that could help us.
Oh yeh, and as Raptor said, what did the black screen say?
Did this really happen? If so, why would IBM prompt for Windows...?