If we have forget the windows password we can reset it using a Linux live cd. Ubuntu is the better option for doing this. We need to have a Ubuntu Live CD
1. Boot from the Linux live cd
2. open the terminal and install the command
chntpw #sudo apt-get install chntpw3. Then move to the windows configuration directory
# cd /media/YourWindowsVolumeName/Windows/System32/config/4. Execute the command
# sudo chntpw SAM you will get some thing like this:
To proceed with clearing the Administrator password account type “1” and hit Enter
5. Now your windows password will be reset and you can login to the windows without password.