If you turn off automatic login, log in as an administrator to make these changes to your computer.
If you know the name and password of an administrator account, click the lock icon to change settings in System Preferences panes when you're not logged in as an administrator.
To keep your computer secure, don't share an administrator name and password with anyone. Be sure to log out when you leave your computer or set Screen Saver preferences to require a password. You may also want to log in as a user that is not an administrator.