I've never really had any issues with WMP except that there was no 4:3 stretching option but since I started using XBMC and then Plex Home Theater I have very little reason to use WMP. Plus when I do just play something from my file explorer I just usually use the new Movies and TV app which does feature aspect ratio settings. The only reason I had removed it was when using Daemon Tools with Sega Saturn files it would load the games and auto run them as audio CDs while at the same time launching SSF. Doing so fixed my issue and the behavior stopped luckly when I re-enabled it today the issue didn't return.