I can’t shut down nor reboot without console
When I click shutdown or restart from login-screen, nothing happens.
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There is an issue for some users in 12.04 and 12.10 where shutdown/restart only logs them out of their user session and does not shut down the machine, and using shutdown/restart from the login screen does nothing. It is apparently just a bug. You can try some of the solutions you may be able to find in Google but nothing has worked reliably for me.
You can still shutdown your computer by opening a tty terminal (CTRL-ALT-F2 through F6), logging in as root, and entering
which will shutdown the system or
which will reboot it.