If you need to reset a Windows password this is the tool you need.
Start by installing the command line application.
sudo apt-get install chntpw
From the man page
chntpw is a utility to view some information and change user passwords in a Windows NT/2000 SAM userdatabase file, usually located at \WINDOWS\system32\config\SAM on the Windows file system. It is not necessary to know the old passwords to reset them. In addition it contains a simple registry editor (same size data writes) and hex-editor with which the information contained in a registry file can be browsed and modified.
Please complete how to. . .