No sound on video file, works on other comps...

I am trying to play a video file on my computer. When I try to play it, the video comes through fine but there is no audio. Youtube and other files of the same type work fine. My first thought was that there was a problem with the file itself, however, when I play the exact same file on another computer, it works like a champ, audio and all. I have tested the file on both computers with both WMP and DivX on both computers.
Computer number 1 has no audio for that particular file but does everything else fine.
Computer number 2 works fine period.
The fact that the file works on other computers but does not work on the first computer no matter what player I use is driving me nuts.
Any pointers?