This has a few scenarios to be ironed out and ask.
1. What type of connections and video card are you using?
If you are using a high end video card, you can use a HDMI connection from your video card to your TV. This will carry both video and sound from the computer to the TV.
2. Do you want the sound from your TV speakers or from a digital sound system in the room?
In that case, you can hook the computer to the TV by any video means capable and have an optical sound out put from the computer to the digital sound system. This is assuming that your computer has an optical soud output.
Some TVs have a sound output, so you can have both sound and video to the TV and have the TV output the sound to the digital sound system.
As you can see, alot more info is needed in order to fully help you with your setup.