Sound Mixer I Have Vista, And Am Having Problems With The Sound Component. How Do I Get The Music Mixer To Open Up?

I have vista, and am having problems with the sound component. How do I get the music mixer to open up? - sound mixer

I have recently installed an audio driver update, but now my speakers shows no sound. This occurred intermittently, for example, I will play in iTunes, for a while, then no noise. The same with a game, the sound, then it stops. I tried to open the sound mixer and my laptop said no components are installed. Suggestions?