Low Sound?

I started to download divx movies after connecting the net by cable. I downloaded Aliens, Blade Runner and a couple of more movies using sig2dat links in fasttrackmovies. My problem is that I can hardly hear the sounds and this is for any movie I downloaded. This problem does not occur in other file types(mp3,asf,mov,rm etc.). Does anybody know the reason for this problem and how it can be solved? There was a program in kazaa codecs(full) and it was boosting the sound, but the sound was being distorted when it was being used. Are there any other programs that make the same job in a better way?Thanks.

By the way, I want to add that I have the right codecs. That is, there is sound in movies, but it is too low that I can only conclude there is some problem with level of sounds.