Sorry, I didn't describe my problem clearly.
I tried two ways.
The first way, I switch to console with ctrl+alt+F#.
X is still runing. When I swich back to graphic mode with
ctrl+alt+F7, I can't see anything, all dark. X should be
still running.
Then, second way, I try to logout(there is a logout option
in Gnome main menu, just like in Windows) and X is stopped.
I run "startx" again to restart X. Again, all dark, don't
see anything.
I am sure there is only one x session at once, and I did
not mean to run multi-x-session. I think
the problem is not how many X seesion I try to run. I
guess it may have something to do with my monitor or driver?
How to fix it? I can rerun my X only after rebooting, very
annoying.
Thanks
> If you go to a console using Crtl-Alt-F# you typically go back to an
> already running X with Alt-F7.
> If you log out of X to the console try 'startx', although, that would not
> be something you could log into as a different user since it would be
> running as the user that started it.