Hdmi or vga cable.
Hdmi is both audio and video and the quality is superior in every single way possible. Its a newer connection so some recievers and tv dont have it. However if your gear is not early 2000s, chances are youll have it.
You can hook it straight from the pc to the TV. However, Id hook one from the pc to reciever then reciever output to TV. If your gear doesnt have HDMI, you are way past due for an upgrade bro. Most 4k hdmi recievers are around 150 to 200 used on
ebay nowadays for a nice onkyo, they used to be 500 to 800 new just a few years ago. Sound quality out of them is amazing with 32 bit DAC processing and dolby digital surround sound. video is crisp as well.
If your comp doesnt have hdmi, you need a mother board and processor upgrade as well... An ssd wouldnt hurt either.
Vga cable is basically the same cable you plug into a computer monitor, its just video only no audio, youll have to use RCAs or spdif or toslink for audio.
If you ever need help with an HT build or setup or pc build, hit me up, ill let you know whats the good sh*t from every price range.