After an inturrupted upgrade from 11.04 I was finally able to get back to a login screen. However, I'm only able to login as a guest.
When I try to login with my regular username, a black box opens up in the top left hand corner with:

(username)@(username)-Satellite-A135:~$

I've tried typing in my username, password...nothing.

I've used Linux for a couple of years and can usually Google my way through things, but this one has me stumped. I've tried commands suggested to users with similar problems, but none of them have worked.

I don't want to mess anything up!! Any suggestions?