I have new mobile phone and have transferred all songs to it. However, only those which are file type 'MP3 audio file (mp3)' come up on the phone by song, artist, album etc. All songs of type 'windows media audio file' just come up under 'unknown' and as such you can't search for them. I have cut all such songs from mobile and saved to desktop. How do I convert a windows media audio file to mp3 audio file?