No audio during Playback

[songpony]

I just got version 2.506 and it works great except during "Play", there is no sound at all. I had tried the 2.508 demo but it didn't support my older Sony CDRW; its "Play" function worked just fine though (on files I had previously recorded to my hard drive). This leads me to believe it's not a problem with my computer, but either a problem or settting in the program. Nothing in the troubleshooting section of the manual, or in any of the menus that I could find. I've seen one or two mentions of "Mute" in other forums, but no information. Any ideas how to resolve this problem? Thanks.