After you upgrade from an earlier version of Microsoft Windows to Windows Vista, you cannot play media files that you purchased from the iTunes Music Store.

Note: You try to play these files in Apple iTunes.

Additionally, when you try to upload a media file that you purchased from the iTunes Music Store to an iPod, you may receive an error message that resembles the following:

Song name was not copied to iPod name iPod because you are not authorized to play it on this computer