help can't get sound out of myhd when playing mpeg 2 file

When I go to play a mpeg2 file recorded in a different program via Myhd I don't get any sound. I know the file is fine because it works in windows media player just fine. I have sound out of the myhd both for digital and analogue broadcasts and out of media player. My sound card is a delta dio 2496 and I am feeding a outboard processor via optical out. What is the proper set up for the control panel in xp to play files.