After wordpress installation what are all the installation files i should remove, to avoid hacking and ensure owner only access. How do i restore the wp-config.php file if one site got hacked.
If you do everything correct - you shouldn't have to worry about being hacked. I assume when you ask what files you remove, you mean from the wordpress - in that case, remove the entire "install" directory (or rename it to something no one could ever guess) As for protecting yourself from being hacked - UPDATE/UPGRADE whenever possible. If Wordpress releases a new update to their script - Update it ASAP. Other security risks - use complex passwords, have an anti-virus/firewall (Free anit-virus's such as AVG and Avira work perfectly!)
also the pentagon is not protected from hacking but if you follow the instructions after installation it will B ok
Update and install protection plugins that help detect problems within your blogs infrastructure. Here's a useful one I use a lot: WP Security Scan (Plugin) As for how to restore a site if you get hacked: I would not worry about the config.php because you can always start a new blog with a new config.php. What's important is making backups of your blog so you can easily restore your blog if needed on that new blog. Use wordpress's Export XML feature under tools in your admincp to accomplish this. Take back ups frequently and keep them updated so if you ever do need them you have them. That's your only true defense again hacking in my opinion; remaining vigilant.