Was upgrading my management desktop recently and somehow forgot the admin password – nightmare!
Anyway, found this excellent resource:
http://www.pogostick.net/~pnh/ntpasswd/
You download a CD image, create the CD, boot to the CD which loads a linux variant and the utility. You can then follow the menu instructions to reset the admin password – their FAQ was useful.
Worked perfectly and their CD now sits in my utilities box.