I hope this is the right area to post this question. So my roommate and friends found a way to change my administrator password on my white macbook. I had never told anyone my password. I was wondering how this could be done and possibly a way to prevent it. One of the friends said they just took the battery out to get around the password but I doubt that. I know they didn't reboot. So could I get some help to be less paranoid in the future?