Originaly from Mark Joseph Edwards, Windows & .NET Magazine Security UPDATE

Have you ever lost or forgotten a user password? Several tools are available that can help you in those situations, including Peter Nordahl's Offline NT Password & Registry Editor tool (see the first URL below). Nordahl's tool is available in the form of a floppy boot disk image, which contains a single-floppy version of the Linux OS along with software that resets any valid user's password. The tool works on systems that have Syskey enabled--a nice touch--and you can also use the tool to disable Syskey. If you prefer to use a CD-ROM-based boot image, DMZ Services offers one that contains a mini-Linux boot image and Nordahl's password recovery software (second URL below). DMZ Services offers a shell script that can create the bootable International organization for Standardization (ISO)-based image and offers an ISO-based file (.iso) that you can burn directly onto a CD-RW using standard CD-RW burning software.

http://home.eunet.no/~pnordahl/ntpasswd
http://www.dmzs.com/tools/files