To set Windows Vista to play stereo sound (mp3 files for example) on all of your seakers on 5.1 / 7.1 sound system you need to set a sound driver option.

1. Go to speaker properties

- right click speaker icon located on task bar notification area near to system clock (bottom righr screen corner). This will open popup menu.

- left click on "Playback Devices" menu item. This will open "Sound" dialog with "Playback" tab selected

- click on "Speakers" item to select it and then click "Properties" button. This will open "Speakers Properties" dialog with "General" tab selected.

2. click "Enhancements" tab to view enhancements options.

3. mark/select "Speaker Fill" option.

4. click "OK" button on "Speakers Properties" dialog to close it applying changes.

5. click "OK" button on "Sound" dialog to close it applying changes.

Now windows vista will play sound on all speakers*

* NOTE: Your 5.1 or 7.1 sound system must be set correctly as 5.1 or 7.1 respectively, not as stereo speaker system!.