How to change default media player and add music folder

[gert]

When I first typed in P to play an MP3, a box came up asking me for my default music player and the folder where my music was located.  How do I now change these?  I can't find a way to bring up that box again.

Also, the default letter to play and MP3 is P.  How do I change that?

Thanks

[bablu2011]

You can scroll and press delete then it would be fine I guess. Cheers mate.