You should try to check the following things.
Make Realtek Digital Output the "default device"
Now, depending on what media player you are using, you may need to go into audio properties and enable Bitsteaming for AC3, DTS, etc, and also look at enabling Passthrough for S/PDIF as in the diagram below. You also need to switch to AC3, DTS or something like that in your Receiver settings as well.
Thank you pjred for trying to help me with this issue.
I have alredy made Realtek Digital output the default device, that didn't help.
Mostly I use Kodi/XBMC as media player, but i have also tried to play 5.1 sound via the browser IE and Firefox (you-tube clips).
I haven't tried VLC-player yet.
I am afraid that I have been a little bit busy the last few days and I haven't been able to work on this problem.
I will be back here when I have had a chance to work a little bit futher with this.
If anyone else have any other suggestions how to solve this, I am very thankful.
Ok, so far so good.
Now the sound works with the Kodi mediaplayer. As pjred said I had wrong configuration in the Kodi sound settings.
I have also tried with the VLC media player, it also works.
All I have to check now is my 'pay per view' and 'video on demand' providers, to check that they works to.
Thanks for you help.
I am glad to hear this is working for your computer.
In case you need more assistance or if you have any questions do not hesitate to contact us back.