After transferring my zune's music collection from a pc desktop to a virtual windows xp on my mac, my old music stopped working correctly. When i try to play zune music on my mac only newly downloaded music will work without internet connection. If my computer is connected to internet, then the old music (which i downloaded before making my computer switch) will play but sometimes it will stop partway through a song. I want to be able to use my zune collection without spending years deleting my old music and re-downloading it; how can I?