try to downoad ac3filter..otherwise..if you have gspot program..try to run it through and figure out which codec your'e missing..otherwise..in the tutorial section from that program..they should direct you to help ..like sometime..it's an mp4 or mp3 audio problem..i ran into one of these long time ago and yeah..it like gave me some program option to use it..but at my own risk so..like i've mention..try to figure it through gspot what codec your'e missing..^^