Thank you.. I well try that out and return to tell What happenI was pointed to this post http://askubuntu.com/questions/10769...tdown-from-gui
from an answer to my question on launchpad.
The answer boils down to this seems to have been a problem since 11.10, although in 11.10 I had no trouble shutting down or restarting.
One person wrote that he found a solution by adding the following line to the file /etc/default/halt:
I added this and so far I am able to shutdown without problem. So I think this is solved, but I'll wait a bit before marking it solved just to be sure.Code:INIT_HALT = POWEROFF