Question about codecs and youtube?

Ok..so here's the dilemma. I uploaded a video, a .mod file I believe, onto my desktop computer (dell). I played it on windows media player, but there was no sound. at first it wmp said "acquiring codec...codec acquired." but it still had no sound. I checked other videos on this computer and they're all like that. But, I don't have this problem on my laptop [which unfortunately i don't have access to today]. So, if I want to upload this video to youtube, will it come out with no sound on youtube, too? Or is that just my computer's problem, and on youtube the video will have sound?