I have further isolated the problem. If I exported an mpg file from Roxio, the sound will play. If however the clip was made in Power Director, it will not play the sound. I make mpgs of 3-7 minutes of my grandkids. When I generate about 60 minutes of clips, I burn it to DVD. However, the clips imported from Power Director have no sound. Roxio should really come up with a fix for this. The program is less than a year old to me.
Thanks especially to Digital Guru for the responses.