[PLUG] How to switch from XTERM to GNOME/GUI

[Pankaj swami]

Hey guys i am using ubuntu 10.04 & I did a very dumb thing, and now
I'm stuck in XTERM mode (where only the terminal shows up).
I switched the environment (via the login screen) from Gnome/GUI to
XTERM. Now, whenever I start Ubuntu, it automatically logs me in, and
goes to the terminal. Is there a way I can go back to the login
screen, or somehow switch to the Gnome environment via a Terminal
command? I tried some of the keyboard shortcuts, but they didn't work.