Things You'll Need
Instructions
Installing a Game Already Owned
Insert the desired game into the Xbox 360 loading tray.
Sign in with your Xbox Live Gamertag.
Go to your "Game Library" from the My Xbox tab. The game in your tray should be the first game listed.
Press "A" on the game in your disc tray.
Select "Install Game," which is the fourth option listed.
Select the storage device you want to place the game on.
Download and Installing a Game from Xbox Live Marketplace
Start your Xbox 360 console.
Select "Explore Game Content" from the Game Marketplace tab. Many titles for the console can be found here, including ones that can be purchased and downloaded to the machine.
Scroll up to find "Games on Demand." All the Xbox 360 games that can be downloaded and installed will be found here.
Select and purchase a game you want to purchase. Unlike with other transactions on the console, you do not have to spend Microsoft Points to purchase the item.