after installing core Raspbian on Raspberry Pi I installed gnome (apt-get install gnome-desktop-environment) but now I am getting authentication failure.
I am being told that not being able to log in as root to graphical interface is a standard security feature of Linux.
So to sort this out, I need to create another user in shell:
Ctrl+Alt+F1 to get to shell
log in as root
then set password
Then reboot and log in to Gnome
Still having an issue with Gnome loading loading properly but this will be Raspberry Pi issue I guess.