Loss of audio to my Window 7 computer

I turned on the Flex 6300 this morning, set the frequency for the High Noon Net and then muted the audio. At 1130 I un-muted the audio but had NO audio. Everything else was fine. I rebooted both the Flex and the computer, no luck. I plugged my headphones into the Flex and the audio is fine. Just none going to the computer (yes, I've checked and the computer audio is OK for every other program).