An input port on your television labeled "RGB-PC Input," or something similar, is used to accept a video signal from a computer. These ports connect to standard VGA cables just like the ones used to connect a desktop computer to its monitor. However, not all computers are able to send video output in the right format for a television to use.
In order for your television to accept PC input, your computer's graphics card must support NTSC output. Check the computer's user's manual to determine whether your graphics card is capable of what may be called "TV" or "NTSC" output.
Connecting the Devices
Connect one end of a standard VGA cable to the television's PC input port and the other to the computer's output port. It does not matter which end of the cable you attach to either device. If you have an old VGA cable that was used to connect a computer and monitor, feel free to use it. There is no difference between VGA cables sold as monitor cables and those sold as computer to TV cables.
Click the "Start" button in the lower left corner of the computer's screen and select "Control Panel" from the menu that appears. Click "Appearance and Personalization," then "Connect to a TV." You will likely have to select an input mode on your television in order to display the PC input. This is usually accomplished by pressing an "Input" or "AUX" button on the remote control. Consult your television's owner's manual if you have trouble.
If you want to use your television's speakers instead of the computer's, you will have also have to send a sound signal to the television. The easiest way is through a stereo to RCA cable. These cables can connect the computer's headphone output to the television's red and white RCA inputs.