The Kubuntu 12.04 desktop has disappeared.
The taskbar is gone.
The icons are incorrect, i.e., the images are either blank or for executables are a diamond filled with two ratchet wheels.
I have run
sudo apt-get install kubuntu-desktop to no avail.
I have also run
kfce4-install, but it did not help.
Previously I could copy
~/.kde4 to somewhere else. Now there is no
.kde4, but there is a
.kde which I have also tried to copy away but that also does not have any positive effect.