id like to add i also am now experiencing this
my old laptop core duo intel, using intel gpu and drivers run amazing, just installed mint onto my desktop pc 12 on a dual boot everything went smooth, then last night an update ran and i also have the static screen on gnome,gnome classic, and cinnamon completley hung only ctrl + alt + back will get me out, no clock movement
the gpu on the pc is ATi also as above? still MATE works super fast (well its faster than cinnamon anyway) no crashes. I have re-installed lots of gnome, cinnamon things again but nothing.