Another thing I'd check is the "Allow applications to take exclusive control of this device"... mine is checked, and everything works fine, but if you have anything in the background that might be grabbing the mic, unchecking this might help:
Another thing I'd check is the "Allow applications to take exclusive control of this device"... mine is checked, and everything works fine, but if you have anything in the background that might be grabbing the mic, unchecking this might help: