Change any XP User Password Without Having to Know the Old One

To know every user account dat exists on a Windows XP machine ? And how to re-password any account without having to know the existing password ?

To view all of the user accounts:

1. While logged onto the computer, click on Start > Run > and type in CMD
2. 
3. From the command prompt window, type in net users. This will show you every account that is made onto the computer even if it is hidden or not.

To change an account password:

1. While logged onto the computer to an account that has administrative rights, click on Start > Run > and type in CMD.
2. Type in net user then the name of the account then * and press enter.
   Example: net user administrator * or net user "John Miller" * (Put the name in quotes if it contains spaces)
3. From there it should ask for a new password. Type in your new password and press enter (type very carefully and check your CAPS Lock because 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've changed the password.