Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
My roommate keeps creating his own administrator account on my mac using this method:

http://osxdaily.com/2010/08/10/forgot-mac-password-how-to-reset-mac-password/

I tried changing the permissions on the .applesetupdone file. Short of locking away my computer all of the time, any ideas on how to protect from this?! I can't believe it is this easy to get past password protection.

Thanks!

Try Filevault2.

If your roommate can get around that please do let us know.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.