How to connect Home Theater 5.1 to PC

[chaosmonger]

Hello guys, I've a 5.1 Home Theater System:
PHILIPS HTS3593
I want to use the same speakers with my desktop computer, motherboard:
ASUS M5A78L-M/USB3
For watching movie, playing games, etc. having a 5.1 output, like when I'm watching bluray from the Philips system (or like when I'm using a true PC 5.1 speakers).

I've tried with the optical cable SPDIF, but no results at all...

I can also buy some extra components for my PC, max budget $150. Like an external card, or some cheap 5.1 PC system to plug the Philips speakers.

I searched around this forum, but haven't found any solutions...
Any suggestions?

THANKS A LOT!

 

[helpstar]

Which 5.1 test do you use? The test in Windows won´t work, that´s just for HDMI or RCA connection.

Which option is set in the philips´ sound settings at the setting "surround": auto, multi-ch or stereo

Here are some demos:
http://www.demo-world.eu/trailers/dolby-trailers.php

´http://www.demo-world.eu/trailers/dolby-trailers.php