How to Change the Password without knowing the old one

How to change computer password without knowing the old one
There are some ways but i willtell to:
Open command prompt(in safe mode)

type:
net user
-this command will show you the users of the computer
-Then type: net user (the name of the user you want to change the password) *
-then type the new password and then reconfirm it.
Note- This trick is valid only for Windows XP, and 7.