Yeah thats kinda right Mderms... It is a well hidden file. It actually only holds the name of your last used profile and records its progress in the campaign mode of halo, as well as a few other settings ingame. It is not hard to edit the file, the hard part is finding it. Once I found it I just burned the file to a disk and add it to my halo program files for any reinstall and use that to create the profile I want. I r haxor. tehehe... not really.
You could always use GOOGLE!!