LOGGING AS ROOT IN UBUBTU

Just follow the steps below:
Open the terminal and type:sudo passwd root
When you see the prompt that says "Enter new UNIX password", enter the password you want for the root user and confirm it.
Type:sudo gedit /etc/X11/gdm/gdm.conf
Locate the line that says "AllowRoot=false". Change it to "AllowRoot=true".
Save the file
Exit gedit, logout and then reboot