Spent weeks trying to figure out why when I would click on an audio file (mp3) WMP would open showing Now Playing then Flash to the Library then Flash back to Now Playing it was an annoying behavior that I had not previously had...I finally found this post on Microsoft and renaming RM PlugIn.DLL to RM PlugIn.OLD allows WMP to work as it used to and should.

Hopefully a fix for this behavior will be included in the next release

http://social.answers.microsoft.com/...1-642d989f21e2