I currently have my PC wired into my TV using with one of those Analogue - Digital gizmo boxes, & a cable from one my speaker sockets on my sound card to my TV headphone socket but I cannot hear any sound on my TV????

I have tried numerous speaker & the microphone sockets on my PC Sound card, & still no sound, I have also tried connecting via the media card reader microphone & headphone socket to my TVs headphone socket but I still face the same problem, so plzzzz if anyone could assist me I would be entirely grateful....
Cheers