not sure whether or not youve decided to do anything to this pc yet, but if you are still locked out of it, i always try a more simplistic approach to breaking into windows accounts.
If you restart your pc, and press either f8 or f12 usually its one or the other you can load windows in safe mode. once in safe mode you will be brought to the windows logon screen where you can choose which account you can log into. but now instead of the usually visible accounts there is typically a extra Administrator account available now that is usually hidden. most of the time this account goes hidden and unnoticed by the basic pc user, so it typically doesnt have a password. once you log in you can remove passwords from other user accounts. now if this is someone elses computer and you dont want them to know about you breaking in then i dont recommend this approach.
