OK! we're getting somewhere..

Right-click on the speaker icon, choose 'Show mixer window', click the Output tag. On the right of the mixer you should see the IEC958 slider, it needs to be ALL the way down.

At the same time you should make sure the green lamp is on for Master and PCM, and those sliders should be up close to the top.

On the bottom left of the mixer click on advanced and make sure the green lights are ON for IEC958 & IEC958 Pla(yback source). Just click them to turn them on/off...

If you saw what I described, you should now be able to play sounds... look for an mp3 or ogg file and click it.. best of luck!

mvh