A media player, such as Windows Media Player, or another, needs to be installed. Most people have one already installed on their computer in order to watch short videos on popular video sites. These players are free, download is easy, and installation never a problem.
Widescreen monitors work best. This is because most programmes shown online are adapted for widescreen sets. This gives the best possible viewing of a show or movie.
You'll have the additional pleasure of viewing programs and movies from around the world, from almost any channel you wish. Paid Television services, while offering a variety of cable networks, cost much more for this service, and they are limited also in what is provided to you. While you may seem to be able to access an enormous amount of channels, compared to what you can get on your computer, it's a tiny fraction of those available worldwide that you can receive on your computer.
Programmes can be watched live, in real time if you wish. Other programs are available at later times, or for limited, predefined periods on some websites. For those who own a laptop, you can watch these shows and movies anywhere you wish, even snuggled in bed if that is to your liking.