I installed Mythbuntu on a vanilla Dell Inspiron 660s desktop connected to an HDMI monitor, and most everything seemed to work.

However, after having used Gnome-Shell for a couple years, I hate the restricted UI of XFCE. So I installed Gnome-Shell via the usual `sudo apt-get install gnome-shell`.

After I rebooted, I saw the normal Dell boot screen, but afterwards all I get is a completely black screen.

I can still SSH into the machine and I don't see anything weird in `cat /var/log/syslog | less`, but then again I'm not sure what I'd be looking for.

How do I get my display working again on Mythbuntu and Gnome-Shell?