How to enable fedora root user account

Login as Normal User.

Open the terminal and use vim or gedit to open the /etc/pam.d/gdm

su -c "vim /etc/pam.d/gdm"

Comment the following line  'auth required pam_succeed_if.so user !=root quiet'

# auth required pam_succeed_if.so user != root quiet

Do the same for "/etc/pam.d/gdm-password

Save the file and logout from GUI. Now you can login as root :)