Question How to connect old audio setup to new pc

[zabik00]

Hi i just found out that i have some old speakers in my house and they were from ~ 1990-2000. It didnt even had an RAC connections, it was from LG. But there was some optical cable and + and - connections for Left Center Right speakers (which i have) and it had around 160W power and etc. etc. But the problem is my computer has only 3.5mm jack connections and i had couple AV receivers which had RAC and i found some cables from RAC to 3.5mm jack i've tried to connect it all but doesnt work. Sorry for my english, it's not my first language.

 

[helpstar]

Which computer are you using?
Is the 3.5mm plug connected to the green port of the computer?
Is analogue audio set as default audio device in the windows sound settings?

 

[zabik00]

Which computer are you using?
Is the 3.5mm plug connected to the green port of the computer?
Is analogue audio set as default audio device in the windows sound settings?

Yes it is set to default device, and my computer has 2 front 3.5mm jacks and from 6 back 3.5mm jacks. i have plugged it in LINE OUT

 

[helpstar]

Which exact model is the old audio device? Maybe it´s labeled on the device?