Go to "http://store.steampowered.com/app/4800/?snr=1_200_200_252_13" and download the game.

1. Go to www.steampowered.com, and click on the button in the left column that says “Download Steam Now” to install the Steam client.
2. Create a Steam account. To do this, you’ll need to select a username and password and supply a valid email address.
3. After you’ve created your account, you’ll be logged into the Steam client. Now you can either search for a specific game title at the top left or browse the games using the menu on the left side. You can also check under Free Stuff in the left menu to try out demos of some of the games.
4. Once you’ve selected a game (our recommendations include Beyond Good & Evil, Bookworm Adventures, and Sam & Max), scroll down to the bottom of the game’s page and verify that your computer meets the necessary system requirements needed to run the game. Not sure if your computer is good enough? Go to the Start menu, right-click on My Computer, and select Properties; this will pull up a screen with your PC’s system properties so you can compare for yourself.
5. Click on purchase! You’ll have the option to pay with either a major credit card or with Paypal. Once the game has downloaded, simply click on the My Games tab at the top left of the Steam client, select your game, and start playing!