I'm actually using gnome, but for the tidbit of help I have to offer (I've only been seriously working w/ Linux for about a week) I don't think it should matter.
Just pressing Ctrl+Alt+F1 will take you to a real terminal.
From there, type
The -r is for reboot.
I know this doesn't really fix your prob, but at least it'll be a quicker and safer way of getting back into the login until the situation's resolved. . . (Which I'm interested in find out how myself)