If you want a root console, try sudo -i and enter your user password
If you really want to enable root, you can enable the root account by setting a password with
Then go to System -> Administration -> Login window
Go to the security tab and check:
allow local system administrator login
BTW, the disabled root account actually has a purpose. It is supposed to make your computer less vulnerable to attacks from the outside and the inside (hmm, i wonder what this command does ...)
also, everything can be achieved by using sudo