In Windows 7 only user for which password needs to change or an Administrator user can change password. As matter of security password should be changed frequently.
- Login to user for which you want to change password.
- Press Ctrl+Alt+Del
- Click on change a password. Enter your Old (existing) password. Followed new password. Again type new password to confirm. Press Enter key.
Password is changed now.
If you don’t know password of the user you can login in to administrator account and change password.