A friend came to me a with a problem with playing DVDs using Windows Media Player. The problem was that although he could play DVDs there was no audio. It seems that it used to play just fine, but stopped.
It turns out that he must have installed or uninstalled something that messed about with Media Player’s Codecs (the programs that control audio and visual stuff on computers).
The solution it turns out was rather simple – just download the AC3 Filter from www.free-codecs.com
When you’ve downloaded it, shut down Media Player, run the AC3 installer, then restart Media Player and you’re all fixed.