For some reason you forgot your password or another user forgot their password this will help you to reset the user password without having their old password.
click on Start>Run>and type cmd
From the command prompt window, type net users
This will show you every account that is made onto the computer whether it is hidden or not.
Change an account password
Login as administrator click on Start>Run>and type cmd
Type net user then the name of the account then * and press enter.
net user administrator *
net user “Joe Smith” *
Put the name in quotes if it contains spaces.
From there it should ask for a new password. Type in your new password (type very carefully – the command window won't display what you type) and once more to confirm it. If you get the message that the command succeeded successfully you entered your new password without any problem.