How are you connecting them? In order to properly connect them you would need a cable like
THIS to plug into the computer. From there you can connect the RCA cables. Then you have to make sure it's pugged into the correct jack on the computer. Without seeing a manual I'd say look in your sound settings and make sure it's set to two speaker sound. Now on the TV end you have to make sure it is hooked up to the correct jacks as well. If you can get a picture of the back of the TV it would help. Also, the TV has to be on the correct video in setting in order for it to work.