Per-application sound settings

Per-application sound settings feature in Vista enables you to adjust sound volume for each application can access your sound device as you see below

Usually, we want to decrease MSN sound because of our cute friends who give us Nudges and Guitar Smash wink while listening to bond team music or Beethoven symphonies loudly, if you don't use per-application sound settings in this case, you'll be homeless :-)

To adjust it, open "Volume Mixer" right click on Speaker Icon in Start bar then Open Volume Mixer. Now you can adjust any opened application displayed by adjusting the TrackBar.