For the guy who wanted limewire to stop stealing the bittorrent file associations. If you go into advanced options, under the tools -> options menu you will find the 'File associations' bar. Click on it and uncheck the box that says '.torrent' files. This should stop it from making the torrent files open in limewire. As to restoring the default program to bittornado, you could -as suggested- reinstall. Also I'm sure there is an option in the bittornado's menu to reassociate the torrent files to bittornado. Least there is in utorrent (which I use :P)
(For utorrent it's under options -> preferences in the general tab at the bottom. It's a big button saying associate with torrent files)