Won't play from HD!

Hi all. I have the WD Live and have been using it with a WD 500 gig HD for several months without issue. Now, it finds the files just fine and loads everything as usual. It just won’t play them! The circle goes around and around on every type of file and just won’t play. I even bought a new WD hard drive to make sure it was not a problem with the drive. It’s not. I am really upset about this, since I can’t play my movies, and I actually just bought another one as a Christmas gift because I loved it so much. Can anyone help?

What firmware version is on the Live?