login as root

I can't login as root when start ubuntu.

I can login as root in terminal using "su" command.

First you have to set the root password by using the command-
" sudo passwd "
Then you'll be prompted to enter the "new unix password" twice, this'll now be your root password. Nor from the login screen, select other users, type in "root" and its password, and login as root.
Hope this helps you..

Thank you sajinsj. I tried as you mentioned but got an error, "Administrator did not allow to login from this session".

Then do this-
In the Admin menu, there is login window option(or something like that), in that there is an option "Allow local system administrator login". Enable that, and you'll be able to login as root.

Then do this-
In the Admin menu, there is login window option(or something like that), in that there is an option "Allow local system administrator login". Enable that, and you'll be able to login as root.

Then do this-
In the Admin menu, there is login window option(or something like that), in that there is an option "Allow local system administrator login". Enable that, and you'll be able to login as root.

Oh sorry buddy, for pasting this thrice, I'm now i my college, the net here is slow. And thus it resulted in pasting thrice sorry for that.
I hyope my previous infromation helps you.

It works fine for me.
Thank you very much for the correct answer and expecting more help from you.