Summarize the following:
A TV tuner allows you to connect your antenna or cable box to your computer, and then use your computer to watch and change channels using onscreen controls. TV tuners for computers are available from most major electronics retailers or through online outlets such as Amazon and Newegg. Many TV tuners allow you to also record footage and save it to watch later, much like a DVR. Slide the tuner directly into a USB port on your computer, or a USB extension cable if the ports are too close together to accommodate the tuner. Avoid using a USB hub, as they usually don't draw enough power. You can also install a TV tuner card into a spare PCI slot on your computer, though this is fairly difficult compared to plugging in a USB tuner. See this guide for details on installing PCI cards. An external USB TV tuner is much simpler to install than a TV tuner card, and is just as powerful. Some tuners come with a built-in antenna. Otherwise, use the coaxial connector to attach a cable from your antenna or cable box to your TV. If you wish to keep your cable box connected to your TV, but also want to connect it to your computer, you will need a coaxial cable splitter You may need to install software that came packaged with the tuner. Follow the instructions that came with the tuner to do so. Windows Media Center supports TV tuners. Start the TV tuner software and follow the instructions to scan for available channels. If you are using an antenna, the channels you receive will depend on signal strength and the power of your antenna.
Purchase an external TV tuner. Connect the tuner to a USB port. Connect your antenna or cable box. Install the tuner software. Scan for channels. Watch TV.