[Keygenmusic]

Код:

[HKEY_CLASSES_ROOT\.mp3]
@=My.MP3.Player

[HKEY_CLASSES_ROOT\My.MP3.Player]
@="DAMN NFO Viewer file"

[HKEY_CLASSES_ROOT\My.MP3.Player\DefaultIcon]
@="C:\\MyMP3Player\\player.EXE,1"  //тут номер иконки для файла

[HKEY_CLASSES_ROOT\My.MP3.Player\shell]
@="open"

[HKEY_CLASSES_ROOT\My.MP3.Player\shell\open]
@="Open in MyMP3Player"

[HKEY_CLASSES_ROOT\My.MP3.Player\shell\open\command]
@="\"C:\\MyMP3Player\\player.EXE\" \"%1\""

По-моему, так