I live in a dorm and a lot of the guys find it amusing to go on someone's computer and screw around with the system setting and load up a bunch of gay porn onto the computer. Is there anyway to have a login and password required to log onto the computer or something to protect my computer from people messing around with it? Thanks p.s. My computer has gone untouched mainly b/c people are scared of my mac b/c they don't really know how to use it. It would be nice to have a safety precaution though.