Anyhow, W7's WMP can not decode many files. Go get VLC PLAYER from Ninite.com to play the rest.
This is not a bug in WMP. It's called a limitation.
WHENEVER I WANT TO PLAY MEDIA ON MY WINDOWS 7 PREMIUM EDITION, IT DOESN'T. INSTEAD IT GIVES MEA MESSAGE THAT "WINDOWS CAN NOT PLAY THIS FILE" WHY THAT?