I got a new imac intel core 2 duo and I am trying to put music from itunes onto my mp3 player. It is loaded with music from my previous G4 emac and itunes. When I plug it in with the usb cable it does't show up on the desk top. I tried it from both the keyboard and computer usb ports. The computer doesn't seem to know it is there. Is there a setting somewhere that I am missing.