How do I fix Logitech webcam w/ built in microphone?

A few years ago I purchased a Logitech webcam with a built in microphone from an Apple store. I bought it to use with my Mac Mini about the time of Leopard or Snow Leopard. After plugging it in to the USB port I attempted to see if the Mac "recognized" the external device. It did not seem to, but I continued to test it by opening up Photo Booth. It did work on PB but tried to record video to test audio and make sure microphone worked properly. Microphone does not capture any audio. I unplugged it and forgot about it. Now I am attempting to use it again with Mountain Lion, but getting the same results. I am looking for a solution as to why video works correctly but still no audio is captured by the microphone. Anyone know the reason? Thanks for any help.