Can't get sound on a dvd movie, but can on my games???

[ar15]

When I play my dvd player I can't get sound from my movies but the video is fine.
I can get sound when I play games though.
What's the problem?
If I have to do a re'enstall of the drivers, where do I go?
I'm not very pc smart (52 y/o) So I need some very detailed help
thx