Setting the Default Audio on your Computer
Whenever you plug a new USB device into your computer, such as a webcam or a combination headphone/microphone, you may have to set your computer’s preferences to use when required for Adobe Connect. The computer will tell you that the device is ready to use, but that can be deceiving.
You will need to go to the Control Panel of your Windows 7 computer (or better) and adjust your sound settings. This PDF powerpoint walks you through the steps, visually.