Speakers connected to pc

[alonsegel]

hello guys.

i have an lg reciver model ht503sh and another 5.1 speaker system from lg aswell.
i just ordered a 2 rca to 3.5mm adapter on ebay because i want to connect it to my pc.
will i be able to hear surround sound when im watching movies? and can i make all of the speakers to play simultaniously?
and if i can't, i have an coaxical input/output (not sure which) on my motherboard so is there an adapter from optical to coaxcial?
thanks and sorry for my bad english

 

[alonsegel]

someone?

 

[batuchka]

Hmm state the exact model LG speaker system and/or what audio inputs the system has? Also state model of motherboard so we can confirm what audio outs it has @ rear