Steps to reset forgotten the Windows administrator password:
1. Insert Ubuntu Live CD and boot from it.
2. Open terminal and install chntpw in Ubuntu. To do so use the following commands.
sudo apt-get update
sudo apt-get install chntpw
3. Now mount your Windows volume. In my case it was dev/sda1. Replace it with yours.
sudo mkdir /media/WINDOWS
sudo mount /dev/sda1 /media/WINDOWS
4. Now navigate to the Windows configuration folder.
cd /media/WINDOWS/WINDOWS/system32/config/
5. To reset the administrator password enter
sudo chntpw SAM
6. After completing this command you will see 5 different choices. Select the 1st one and press Enter and its done.
7. Now restart your system, it will not ask any password.
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