Perform a Clean Install of OS X Mountain Lion on Startup Drive
It includes information on the decisions you make when performing a clean install. Do this using Disk Utility, which is included with the installer. Insert the bootable media or connect it to your Mac and then restart the Mac while holding down theOptionkey. You can choose to transfer user data, applications, and other information from another Mac, PC, or hard drive.Screen shot courtesy of Coyote Moon, Inc. The Mac OS X Utilities window displays as if you are booting from the Recovery HD partition....