MacBook Air (Late 2008 and Mid 2009): How to ‘Erase and Install’ using Remote Install Mac OS X

Use this procedure to restore the original factory settings and the software that originally came with your computer. You will use the DVDs that shipped with your computer and another computer on your network that has an optical drive. This procedure has three parts: Restore the Mac OS X Operating System using the Remote Install Mac OS X. Complete the Mac OS X Setup Assistant. Restore Bundled Applications using DVD or CD Sharing and the Applications Install Disc. Important: This procedure will completely erase the contents of your hard disk.  If you have multiple partitions, it will completely erase the partition you select.