I'm running W7 Utlimate 64 on a Dell Inspiron desktop. WMA, MP3 files (podcasts, ripped music) no longer play in either Windows Media Player nor Zune desktop software (to be clear, I don't have a Zune portable). I can play these MP3s over the network on other computers, so the files are fine. Files play on my Android phone. The Zune software player acts as if it thinks it is playing an MP3. You can see the scrub bar progress, and the animate spectrum analyzer work.
System sounds, Streaming browser media (audio, video) sound just fine. Cable TV sounds fine in the Media Center.