Great guide but you missed one important step. To restore from a backup. Every computer user should be making regular backups so that they can avoid having to reinstall their OS which should always be a last resort.
Check out my guide on how to create a bootable backup of your Mac on my blog at http://blog.clydetech.co.uk/2006/07/mac-os-x-creating-a-bootable-disk-backup/
Clydetech
A Beginner's Guide to Fixing OS X