Hey maddielou2,
Thanks for the question. The following article outlines a resolution to your issue:
Songs in iTunes may not play back completely
http://support.apple.com/kb/TS4357
Occasionally, if a song purchased from the iTunes Store on a Mac or PC was not downloaded completely, the song may not play back fully. The song may abruptly stop during playback, and iTunes may start playing the next song in your library or playlist.
Resolution
If iTunes in the Cloud is available in your country, try the following steps to resolve the issue:
- Delete the purchased song that is exhibiting the problem from your iTunes library.
- Click on the Purchased link in the iTunes Store to view your previously purchased music.
- Download your previously purchased song from this list.
Thanks,
Matt M.