5.1 audio problem with new mobo

[illgamma]

this is off topic but i cant find any solutions for my problem and u guys are as smart and any other forum. i just finished building my new pc with a gigbyte ga-7n400 pro2 mobo. i have logitech z-680 and i want to connect my new pc to them with optical. i cant get true 5.1 sound from the speakers just 2.1. i think i need to output with DD pro logic 2 but i dont know how to do that. does anybody here have this setup too and know what i can do? i cant use the analog inputs because they are for another computer.

[offline]

I'm moving this to the computer forum but I will make
one comment. You need software to output DD 5.1, even
after configuring the on board sound software to play
5.1.

You can't just activate the digital out and that is it!

If playing music, you need a player that will output
Pro Logic II. If you are watching movies, you need
a player like PowerDVD that will output DD 5.1