This is a utility to (re)set the password of any user that has a valid (local) account on your NT system, by modifying the crypted password in the registrys SAM file. You do not need to know the old password to set a new one.
It works offline, that is, you have to shutdown your computer and boot off a floppydisk. The bootdisk includes stuff to access NTFS partitions and scripts to glue the whole thing together. Note: It will now also work with SYSKEY, including the option to turn it off! More information here. Download here.