I have Windows 7 Home Premium and a Realtek High Definition Audio card thing. My microphone works perfectly. When I make a sound the mic "confirms" me that it can "hear" me. Stereo Mix on the other hand doesn't. It was working just a couple of days ago. I've tried all combinations. Disabling the mic and enabling stereo mix, enabling both... all possible combinations. Last time I remember it working, I was recording something with the "Sound Recorder". It simply stopped working, suddenly.