Mixer Device is a Windows utility that controls the audio on a computer. The Mixer Device Volume Control helps computer users mute sounds, or turn the volume up or down. With a corrupted Mixer Device utility, you would see an error message that reads: "There are no active mixer devices available." The utility needs to be reinstalled and re-enabled through Windows to fix the volume and sound control. Click on the "Start" icon. Click on "Run" if you are using Windows XP. Type "services.msc" (without the quotation marks) into "Run" and hit "Enter." If you are using Windows Vista, click on the search field and type in "services.msc" (without the quotation marks). Hit "Enter." Double-click on the "Windows Audio" icon. Click on the "Startup type" drop down menu and select "Automatic." Click on the "Start" button under "Service Status." Click on the "Apply" button to confirm your changes. Click on "OK" to close the window.