It is so till login screen. I mean that when I boot my computer, Ubuntu shows a splash screen with mouse instead of Ubuntu logo and in the login screen it shows XUbuntu login screen... It began when I upgraded to previous kernel, I suppose, but I'm not sure... I can't say that it annoys me very much, but I would like to see what I got... What is the reason of such strange behavior and how can I make my system shows correct labels?..
Go to
Administration -> login screen and then change your login window 
1 Like
Found something
http://ubuntuforums.org/showpost.php?p=7576112&postcount=365
http://www.ubuntumini.com/2009/09/hack-karmics-gdm-login-screen.html
something maybe offtopic but surely useful if you find a solution:To change your login screen background you must replace the /usr/share/images/xsplash/bg_2560x1600.jpg
to your preferable image with the same name.
Appears you installed Xubuntu over Ubuntu...
Wouldn't the installation for Ubuntu format the partitions? I installed xfce the other day on ubuntu 10.04 and it did change the login screen but not much was different other than the login screen.
Or is xfce not Ubuntu with xfce less gnome?
OP, on the login screen, after you enter your username, there shold be a dropdown box for "session" that will allow you to switch back go gnome.