If you are using gdm you have to run gdmsetup. The option you are searching for is in "security" tab.
If you don't use gdm i can't help you.
Ivan Ivanov wrote:
Dear Colleagues,
I am using Fedora Core 2 with KDE and GNOME. I would like to know whether it is possible to prevent root to log in them and if it is what configuartion should I make?
Thank you in advance
Ivan