New Patreon Tier and Early Access Content available. If you would like to support AVForums, we now have a new Patreon Tier which gives you access to selected news, reviews and articles before they are available to the public. Read more.
Have a look at the back, side and front of your TV for an input labelled PC audio in OR VGA audio in or something similar. If there are two holes which are red and white then you need the first cable. This is most likely.
The other end goes into the headphone out or line out connector on your laptop.
By the way, it really helps to post the make and model number of items you are asking questions about (the laptop and PC in this case)
Most if not all the newer TVs will have a 3.5mm input next to the VGA input for sound, so for sound you would need a 3.5mm - 3.5mm lead from the laptops sound output, normally the headphone out to the 3,5mm input on the TV, as Gadgetcity says posting the make/model of the laptop/TV would help people to give you the exact answer.