Not all play DVD. Try VLC PLAYER to test if that works.
My dvds sound wouldnt work with windows media player or windows media center. The picture would show but there wouldnt be any voices only some music and background noise for some reason. I already tried to change the settings but it still wont work. It did work once when i put on the subtitles but they get annoying so i turned them off. when i turned off the subtitles the voices were also gone and left me with some weird background noise thing. pleas help thanks.