Vista Passwords

Okay, I know how this is going to sound. I work on computers on the side, and I have this 80 year old german lady that has forgotten her login password to Vista. I have try booting in safe mode to bypass it but I did not see a safe mode option. Dell tech support said that I am going to have to reformat the computer to fix it. She does not even want a password on there her grand kid set it up like that and she went on a month long vacation to St. Martin. So…. any ideas?