Install a program called chntpw$ sudo apt-get install chntpw
After successfully installing chntpw, you have to access the Windows NTFS partition by mounting it and allowing read/write support. After that, use your command line skills by navigating to WINDOWS/system32/config
Once inside the config directory, issue this command:$ sudo chntpw SAM
A long display of information will follow. Just ignore them.
Once you are prompted to reset the password, it is recommended to leave the password blank with an asterisk (*).
Reboot, and you can now login to Windows with full administrative access.