A mess with default apps/files converted

So as I was trying to open a bgl file with bglanalyze, I set the default file to open the bgl files (unintentionally) with bglanalyze. Unfortunately, this made all bgl files appear to be open-able with bglanalyze, which I wasn't too fond of.

So I re-did it, and decided to make the default app to open bgl files afcad....

A few steps later, and files which were originally cfg or text became bgl files... Apparently because you can open a file with a certain app, that makes it a different kind of file! So now some cfg files (once filled with text) have been turned into bgls, and when trying to open with notepad, you will see nothing but enriched text...

Help me, I fear this isn't reversible and LOTS of files are probably no longer editable :( .

EDIT, actually this may be a false alarm, since after looking around it seems only a panel.cfg file on my desktop has become rich text (it became a bgl file) upon opening with notepad; aircraft.cfgs and other cfgs elsewhere (in the sim folder) appear to be fine. Sorry for this unnecessary thread if this is the case.

If it only affects the one file try the following:

Right click on the file and select properties - a new window will open. On the General Tab under the Type of File/Opens with section click on the Change button - a new window will open - select the required app you wish to associate with opening the file.

Also not that an option is available to Always use the selected program to open this kind of file - if you wish to do this simply ensure that the box is ticked. press OK to confirm the change.