Get access to local Windows machine using Kali linux

Almost all versions of windows password is saved in SAM file. This file is usually located under /Windows/System32/config. On your system it may look something like this: /media/hda1/Windows/System32/config. Below is the screenshot.

Type command chntpw -l SAM and it will list out all the usernames that are contained on the Windows system.

The command gives us a list of usernames on the system. When we have the username we want to modify and we simply run the command chntpw -u “username” SAM

In the example below we typed: chntpw -u “Administrator” SAM and we get the following menu:

We now have the option of clearing the password, changing the password, or promoting the user to administrator. Changing the password does not always work on Windows 7 systems, so it is recommended to clear the password. Therefore you will be able to log in with a blank password. You can also promote the user to a local administrator as well.

Pasted from: http://kali4hackers.blogspot.com/2013/07/how-to-reset-windows-password-with-kali.html