When initially installing Centos with a minimal install, the Gnome desktop package is not installed. If needed at a later time, it can be installed from the prompt. Steps:
1) run ‘yum groupinstall basic-desktop desktop-platform x11 fonts’ from the prompt
2) that will install the basic items needed for a Gnome desktop to function
3) to have Gnome start when the PC boots up, edit /etc/inittab and make the necessary changes.
4) Next step is to create a super user to perform administrative tasks. Tutorial can be found at: http://youtu.be/aGQB3fXi3nw