I go to the iTunes Store to purchase a song and when I find the song and click on it to purchase I get a message saying that I have already purchased this song in the past. Do I wish to purchase it again? I click on cancel and go look for the song in my Purchased Folder and can not find the song. This has happened on a few songs. How do I get all the songs that I have ever purchased to show up in my Purchased Folder?