Audio S/PIDF Optical toslink

hello please can some one help!! I am a 46 year old man that has a large colletion of music on Mini -Disk I don't what to rip/copy/burn just want to listen
i'm trying to connect my Mini-Disk player to my PC
the motherboard is (Fatal1ty FP9-IN9 SLI)
and the mini-disk player is a Kenwood DMF 3020)
both have optical out-put on and thats the way i would like it... everthing seem to be right BUT i can't here no sound from the speakers only sound i get is if use headphones Thanks inadvance sorry if this is in the wrong place