Things You'll Need
Instructions
Purchase an official Xbox 360 hard drive. Official hard drives offer different amounts of storage space. They range in storage capacity from 20 gigabytes to 250GB, but all versions are compatible with the Xbox 360 Arcade system.
Turn off and unplug your Xbox 360 Arcade.
Turn the Xbox 360 so that you can read the words "Hard Drive." This phrase is printed in large letters on the top of the Xbox 360.
Align the hard drive with your Xbox 360 Arcade. The hard drive will have a narrow side and a wide side. Place the narrow side of the hard drive so that it faces the front of your Xbox 360.
Press the hard drive down onto your Xbox 360. Start by pressing down the broad side of the hard drive and then proceed to pressing down on the front side. The hard drive will make an audible click once it is fully attached to the Xbox 360 Arcade. The click occurs when the one plastic connector on the Xbox 360 locks the hard drive in place. Once the hard drive is attached, the Xbox 360 will automatically access the hard drive and you may begin using it immediately---you do not need to format the hard drive or make any other adjustments for it to work.