Is that a "home theater in a box" set-up (receiver/dvd player all-in-one and speakers)? If it's is, all I could find is that it has 2 composite (RCA type) inputs. Since the TV's only output (as far as I could see) is an optical connection, then it won't work. Sorry...
It's kind of a tough thing that you are trying to achieve with what you have. If I understand correctly, you want to watch TV shows in surround sound. Your computer speaker set-up is really meant to work with a computer-their only inputs are gauged around computers type connections, not home theater type connections. As for you HT in a box, since it incorporates everything into the receiver (and being a but older), it doesn't have any digital inputs (optical). I hate to say it but what you probably need is a A/V receiver. You could probably pick one up cheap, and use the Sony speakers.
I have my system set-up so basically everything can run through my receiver (sound wise). But I also run direct connections from my components directly to my TV so that I don't have to always listen to it with the stereo blasting (HDTV cable box, DVD player). I'm in the process of building a HTPC, which I will do the same. I don't have to rely on using my "audio outputs" from my TV to feed my stereo.
Best of luck to you bud...
