Administrator password can be broken by replacing sam file in system32\config by the sam file in repair folder of windows.
it can be easily done on a machine with dual operating systems, simply log on to os other then the one whoes password is to be cracked
the way is exactly same as written above
but if there is a single os on a machine then there is only one way i.e to use ms dos start up disk or some other boot disk and replace the sam file in config folder with the one in repair folder
note:- this method works only if hard drive is FAT32 formatted because NTFS drive does'nt take boot from Ms DOS
This way you can remove the old administratOr password as if the windows is newly installed and the password was'nt set

Other Way:You can download John the Ripper. That should work.

Or as told by many of ma friends: Creating local recovery password disk....

Do leave your comments if you have some more methods....