I burned several back up DVDs and they all play fine on my stand alone player but when I try to play them on the laptop (Dell Inspirion 8100), I get no sound. I have checked the laptop with sound from an internal file from the "My Music" demo and it plays fine so the problem isn't with the hardware of the laptop.
I really don't know or even know how to check. An original DVD will play on the laptop (picture and sound) but not one copied but the copy will play (sound) on the stand alone.