Not to be mean or anything, but you are being pretty vague. is this on your computer or TV. If it is on your computer (assuming it is) those here need some more details. Do you have onboard sound (speakers plug into motherboard) or a PCI soundcard (such as a sound blaster)? Can you give us the model of your motherboard or soundcard, depending on which it may be?
Concerning the video. Again, integrated video or PCI Express/AGP video card (depending on age of computer).
Finally, is this a prebuilt computer (Dell, HP, Gateway, etc) or a custom built machine?
Answer those and provide us with more details (if possible) and we will see if we can help you out some more.