I'm trying to connect to my new receiver using SPDIF out, because I can't get it to work any other way (HDMI isn't recognized, no sound from RCA), but am having problems because windows 8.1 won't recognize that anything is being plugged in (whether it be an hdmi cable or my optical cable). Yes, my optical cable is working because yes there is a red LED that is on. I am using an ASUS z87 plus motherboard with Realtek audio installed, and as my graphics card I have a Sapphire 7970. Please help I am at my wits end because I bashed my head against a wall with the same problem with an old receiver for a week or two. Yes I have read the manuals and am using the right input setting on my receiver (Yamaha rx-v677).