Microsoft it closing down support for tracks purchased under its failed 'PlaysForSure' campaign. The company is warning customers - who paid good money for music using the now defunct MSN Music service - that it will no longer supply authorisation keys for the tracks they bought.

What this means is that after August 31, music fans who want to shift tracks from one computer to another will be blocked from doing so. It also means that once all five Windows PCs a user can have authorised for music playback have failed, they will lose their music.

The company warns its customers: "You will need to obtain a licence key for each of your songs downloaded from MSN Music on any new computer, and you must do so before August 31, 2008. If you attempt to transfer your songs to additional computers after August 31, 2008, those songs will not successfully play."