With all the good intentions you can think of, name it a tutorial purpose or something to learn purely for the fun and never to harm anyone, I will now show you a simple way to hack a Windows administrator password using Linux. You will only need a Live CD, and for this example, we will utilize Ubuntu.
Boot into the system Which you want to reset by using the LIVE CD:
1. Install a program called chntpw
$ sudo apt-get install chntpw
2. After successfully installing chntpw, you have to access the Windows NTFS partition by mounting it and allowing read/write support. A good tutorial on how to do this can be found here.
3. After that, use your command line skills by navigating to WINDOWS/system32/config
4. Once inside the config directory, issue this command:
$ sudo chntpw SAM
5. A long display of information will follow. Just ignore them.
6. Once you are prompted to reset the password, it is recommended to leave the password blank with an asterisk (*).
7. Reboot, and you can now login to Windows with full administrative access.