Windows 8 Cannot change how a file opens (What application opens it)

First off I'm running Win8.1

Situation:

Well I have a Gmod server and I'm trying to convert some of these gma files with a converter.
I need to open the file with the converter to have them convert but whenever I would choose to pick the converter it would still be the same and not open it or change it.

I got tired of trying to figure stuff out and messed around in the regedit which was bad and what I did was:

Changed the gfx VLC key name to gma

Created a new key below it named
gmodconv
(the name of the converter app)

Changed both data strings to file locations to the converter

Closed and saved




And then what happened after I restarted my computer was:

All the previous GMA files looked like VLC files, default opened with VLC and you couldn't change them

Type of file said VLC media file(.gfx) (.gma)


-------------------------------------------------------------------------------------------------------------------------------


What I need help with:

To fix the regedit problems I caused by editing the file (I tried changing the gfx file back to normal but my gma files still look like they were after I edited the regedit)

And I'd like to know how to fix the problem where I can't change what application a file opens with.


Thanks for spending your time and reading this, and or your help.