Sound problem with Windows Vista: Error: No audio output device is installed

Windows Vista problem with lost sound: Error: No audio output device is installed

 

Many users of Windows Vista are losing sound on their computer. Usually because of updates. I lose my sound and find a red x over my sound icon. Then I get the error message "no audio output device is installed"

Here is a link to a tutorial for Windows VISTA USERS on how to activate the stereo mixer:
Problem recording from sound card: No Stereo Mix option