OS X boot disk and fresh install - mhulse/mhulse.github.io GitHub Wiki

Visit and follow: http://www.macworld.com/article/2055589/how-to-format-a-startup-drive-for-a-mac.html (apply steps to at least 8GB thumb drive).
Follow steps here: http://www.macworld.com/article/2056561/how-to-make-a-bootable-mavericks-install-drive.html TL;DR: Have "Untitled" drive mounted and run: sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Mavericks.app --nointeraction

While the boot disk would work for a fresh install, it's probably best to:

Make a backup of OS using something like Carbon Copy Cloner or SuperDuper.
Make sure you have the latest OS version installed; I've read it's best to do a dirty install of the latest OS (say, Mavericks) … Download that directly from app store and re-install. The goal would be to make sure the recovery partition has the latest OS bits needed for a clean fresh install of the OS.
Next, boot into recovery mode (hold down option key during restart).
Go to Disk Utility and wipe main drive (Extended/Journaled).
Go back to recovery mode main screen and install OSX fresh.
Done.