How to put or drag a song in the runtime to your game and save that song into the game??

This question is very difficult and I dont know if its, but some one know if its posible to something in your game that you can drag only songs in the folder were you have all the songs(out of unity)into the game(during the game is playing) or maybe a little more difficult, how to make something that when you clic it appears the folders and all that stuff were you have all the songs(out of unity) so you can choose the song you want to put in the game and when you stop the game the song you choose it appears in the project.

Really, please if someone know how to do it or you know a different wy to do it please tell me I really need different answers.

Woah, that was one long sentence :)

You can't add assets at runtime, that appear in the project afterwards. That wouldn't make sense since when you build the game, people don't have a project folder.

You can add assets at runtime that are used during runtime. Something like this could be your open file dialog, and then you could stream the file with the WWW class(atleast, I think that would work) Unless you are deploying using webplayer, in which case you can't do it.