If you ever wanted to Login into to your root a/c in Debian and also in other Debian based distros, this is the way of doing it. I think the same works for other distros. But I have got no time to test them out.
Fatal Warning: You are logging into your 'root' a/c at your own risk. I or my blog is not responsible for anything that happens to your Distro due to this post. Thanks and know what you do before you do.
1. If you have a working GDM/KDM - the solution is easy.
[A GDM is a Gnome Desktop Manager and KDM is a KDE Desktop Manager]
2. If your step 1 is not working fine - then you may need to configure your xserver first.
3. Before you login to your normal a/c at the GDM/KDM's Login Screen and once you get the Login screen - follow below:
4. Type Ctrl+Alt+F2 - [the functional key(s) F2 or anything till F5 / F6 and not F1]
5. You would get a command based login prompt.
6. Now type the user as 'root' and input the root's password.
7. Then issue the command 'gdm' if your default desktop is Gnome or 'kdm' if your default desktop is KDE.
So now - you are logged into the root a/c.
Note: If you dont want to login into root, then you can logon to your normal a/c credentials at step 4 itself. That will also take you to your default Desktop.
Note 2: But in case - you want to login only thro the colorful login screen(s) - then type Ctrl+Alt+F7 to get back your Login screen.