fightclub1983 thats low what you did. I think others have emphasized that well enough.
Now for the good news. You can redeem yourself by giving the computer back to who owns it. Im sure you can find out who owned it by whats in his laptop, right?
Turn it in to him. Even if you mail it anonymously. You will feel better about yourself. Also, life has a funny way of getting back at you for doing things like that. Might as well get in good graces ahead of time.