There are a number of ways you can plug a computer into a larger screen. You can use HDMI or VGA cables to do so or even connect through wifi. 

Here's a site that walks you though the steps, and gets you to identify the kind of computer and TV you are using, and suggests ways to connect the two:

Here's an article you can look through to identify the kind of connections you have on your computer and TV.

Here is a video explaining some of the basics of how to connect your computer to your TV.

The solution we like here in the office is an Apple TV and a laptop with OSX Mavericks installed on it using a feature called AirPlay

Apple TV: