AC3 Audio codec problem

Hi
I encounter some problem about ac3 codec. When i look at the video which i try to play with gspot it says codec is installed but when i play the video no sound comes.

I read another thread about this problem and download the codecs from http://www.divxmovies.com/faq/#4.4

but it doesnt work neither. I cant even play the video files i used to play before.

Thanks for the helps

Come on pls help me!