Bottom half of display is black or flickering grey cloud. In top half,
black lines start to dislay in mid dislay and eventuallhy reach top.
Faint images of text I was working on yesterday is supermimposed. One
virtual desktop can't be accessed and instead displays another. Mouse
and keyboard operate normally.

My intuitiion was that this is an X window system problem, but
reinstalling then did not help. is it the motherboard? When I boot
to another drive the problem appears with it as well