Hi, I would like to re-format my HDD and do a completely fresh re-install of Mavericks. I've had the iMac since January 2011 and have loaded every release Apple has produced over top of the original system. I'd like to start from a clean slate. Is there somewhere I could find a procedure to do this? I can have Time Machine make a total backup to use as a place to restore my personal files from. If I make one of the USB boot drives is that the best way to start the re-installation of the OS? Any assistance appreciated.