Volume Control — windowssystem32sndvol32.exe
Start → All Programs → Accessories → Entertainment → Volume Control
Tray → Double-click yellow speaker icon (if it's there)
Volume Control displays volume and balance adjustments for all the different sound devices, such as the audio CD volume, microphone volume, and line-in volume. To choose the controls that are shown, or to hide those you never use, go to Options → Properties, and select any of the following (note that different sounds drivers may omit some of these, or even add additional entries).