Yep, as retsaw said, just typing "root" in x-terminal should change your role to 'root', if rootsh is correctly installed.

If you do "sudo su -", and it asks a password, then you somehow have configured password for a normal "user".

'root' is practically same as 'sudo su -'

'sudo gainroot' is not the same, as it won't change home directory and PATH variable may be different than for a "real" root.

If you have ssh-server installed, then you have also root-password set. You can ssh internally also:
ssh -l root localhost