Need help with Windows Media Player

[Jeff Samco]

Windows Media Player has been my default player for a long time on my 
Windows 7 laptop. IN the last week I noticed it no longer plays any 
MP3 files I press Enter on. Coincidentally, about the same time I 
have subscribed to the eMusic web service. WMP still comes up but the 
track is not played. I have tried forcing play with Ctrl-P and also 
going into the menus. I have also poked around all the menus but 
didn't see anything obvious that needed a setting to be changed.

Any suggestions on how to further trouble shoot this?
Thanks,
Jeff