According to Microsoft, Windows Media Player 10 installation package may overwrite certain Digital Rights Management (DRM) files. The mismatched files prevent protected content from playing.
Microsoft proposed the following resolution:
A supported update is now available from Microsoft. We recommend that you apply this update on all systems that are running Update Rollup 2 for Windows XP Media Center Edition.
This update will NOT fix the problem on systems that are experiencing the problem. However, this update will prevent the problem.
For detailed information about the problem or to obtain the update, please visit the link below.