Windows XP lock feature

I am asking this for my roommate. She has a Gateway laptop running XP home. Her XP locked her out. She can't enter her username or password because nothing shows up when she types. If she hits enter it works, but when she types in text, nothing shows up. The mousepad works ok. She can't ctrl-alt-del her way out, nor hit the power button. The computer is just stuck on that window. She said that she is never had this happen before. Any ideas?

 

Remove the battery and the power cord. The PC WILL shut down then.