Microsoft already killed off its MSN Music service, and now it is kicking those stranded users in the teeth with the announcement that it is shutting down the servers that manage MSN Music PlaysForSure licenses. The servers will shut down on August 31, 2008, leaving everyone that purchased DRM-laden tracks from MSN Music without any way to authorize the music for playback on additional computers, according to Ars Technica.

Once Microsoft shuts those servers down, jilted customers won't be able to authorize the tracks for playback on different computers, deauthorize computers, or even change the version of Windows they use. Since the digital rights management copy protection technology in tracks purchased from MSN Music also requires users to reauthorize if they upgrade to a new version of Windows, they are essentially stuck with the computer and operating system they have on August 31 if they want to continue playing the music they bought.

Microsoft's move underscores one of the inherent problems with DRM and copy protected music purchases: Customers are at the mercy of service providers, and could lose the music they purchase at any time if a company closes shop or changes the copy protection schemes it imposes on its users.

PlaysForSure users have a little breathing room until August 31, but after that their tracks will become PlaysUntilYouNeedToAuthorize.