Start from the Installation disk by holding the "C" key down. On the second screen the pull down menus will appear at the top of the screen. Go to Utilities. Pull down to "Disk Utility" and format the drive. OSX extended journaled will be fine. Now you can continue with the system installation. When finished reboot from the hard drive and go under the apple in the upper left hand corner to "software update". Download and install the updates. Repeat this till there are no more updates. That's it.