cant find download button on previous purchases
need to download a song again, but cant find download button in purchased.
What country are you in - music can't be re-downloaded in all countries. If you are in a country where music can be re-downloaded (and it's still in the store) then it should show under the Purchased link under Quick Links on the right-hand side of the iTunes store home page on your computer's iTunes (if you still have a copy of the song in your iTunes library then it won't show as re-downloadable as iTunes will assume that you already have it).