Surround Sound managment

[alexhs1121]

Evening folks from Germany. I'm a student in mechanical engineering and short on budget. Although I'm quite into technology and PCs i can't figure out this problem by my self.
Setup:
No sound card. only mainboard outputs + front audio output
2 speaker sets: 2.1 and 2.0

What i'd like to have: Surround sound without buying a soundcard (because no more pc slots)
What i tried: 2.1 in mainboard output, 2.0 in front output.
what i think could be the answer but dont know howto: a software that lets me handle mainboard and front outputs seperatly.

Is there a way to get this working or should i invest in a usb soundcard?

 

[alexhs1121]

So i tried a bit swaping cables and so on. I had a green (stereo output) , blue (stereo input) and red (mono input) and luckily my mainboard turned out to have a multiusage for the blue stereo input so that i could put my second pair of speakers in the blue one.