Movies have no sound on laptop

I have an Acer laptop with Vista. I've been using Windows Media Player. Speakers work on everything else okay, but now there is no sound when I put a movie in the DVD player.
I've tried going to K-lite Codec to download that because Acer says it's not a hardware problem, and gave me that link. But it got too technical in asking me what I want to select. Didn't know how to answer all their questions(!).
Tried other sites that guarantee they'll fix the problem, but they always lead me to a product I have to purchase. I've been working on this all night and I am way beyond frustrated.
Any EASY solutions for someone who isn't quite a beginner, yet not bright enough to figure this one out? Need this fixed ASAP, please.