I'm having problems with Unity on a slow laptop, but it's configured to autologin so I never see the login screen. Also, the screen or display driver is messed up so I don't see the far right part of the display.
I had already installed Lubuntu/LXDE earlier and I'd like to try logging into that instead -- but I can't get back to the login screen to set that as the desktop system for the user. The logout command gnome-session-quit doesn't work; I end up in the screen "the system is running in low-graphics mode".
The setting for a given user's desktop environment (Unity vs LXDE) is presumably in some text file somewhere. So if I could edit that file and then force a reboot, I'd achieve my goal. Help?