I've upgraded 3 of the 6 computers in our home network and have hit
some problems. On 2 computers I've noticed that the Power Off sequence wont
shut down the computer after selecting Shut Down. These were upgraded from
11.04. On the 3d machine, an older Dell, it was upgraded from 10.10 to
11.10, (I know, BAD) and once booted up, nothing works, yet you can move the
mouse. Mouse clicks and various keyboard combinations do nothing.

Are these common failures?