I have a Dell XPS 8300 Windows 7 with a sound blaster titianium card I can not get the optical out put to work with my Z 5500 speakers so I tried hooking it up to my harmon Kardon AV 635 and nothing> I have selected spdif out on my Computer and I get a red light out of the cable. Also on normal usb speakers I get sound I am technologically dyslexic and I have an idea that the fix is probably something simple and obvious hopefully.