There are utilities that can crack the password, but the "official" method is a reinstall.  There are practical reasons for this too:  1) you may not want to be responsible for data left on the drive, and 2) the XP installation may be compromised, either intentionally or unintentionally.  You are better off reinstalling.
I bought a Dell Inspirion several years ago and enjoyed it thoroughly. Unfortunately, it was ruined by a move. I recently purchased another one at an auction and was excited to get it home. To my dismay, I turned it on to find an administrator password locking me out. I have tried everything I can think of to get around it, including going through Safe Mode. Safe mode created a new Administrator account that is also password protected. It removed the guest user when it created the new admin profile. If I try to do F11 it says unable. I really don't want to wipe the system and re-install Windows, but will if I must. Just not sure how. lol  I am at a complete loss. The laptop did come with a re-installation disk for Windows XP Professional. Any other ideas?
bought dell inspirion 6000 at auction and it has an unknown admin password.