I wonder why I cannot turn off correctly. Whenever I try to turn off, it get a black screen and it turns back into Ubuntu. Only Ubuntu, HP4140 mini.
4 Answers
Alternatively , you can shutdown your PC from terminal with this simple command .
sudo shutdown -h now
hope that helps.
It sounds like you're actually trying to suspend to disk, but you don't have a large enough swap area to fit all your RAM (that's exactly how my laptop behaves under those conditions).
Are you shutting off with the power button (i.e. hardware switch) on your laptop, or by clicking in the menus in the desktop environment?
If you're using the power button, make sure it is actually mapped to "power off", and not to "hibernate" or "sleep". I don't know which Ubuntu version you're using, but there are good resources on how to do it both in 11.10 Oneiric and a couple of different ways in 12.04 Precise. If neither of those help you, use Google to find some other way ;)

- 2,922
I had an issue with my Lenovo laptop where it would power back on (from the very first screen) whenever I shut it down. It turned out to be an issue with laptop-mode, specifically the runtime PM setting. If you're using laptop-mode, try turning it off and rebooting it twice to make sure the problem still persists. If that solves the issue, then enable laptop-mode but go to
/etc/laptop-mode/conf.d/
and edit this line in runtime-pm.conf:
CONTROL_RUNTIME_PM="auto" (or "1")
to
CONTROL_RUNTIME_PM="0"
Then reboot a couple of times to see if the problem persists.

- 1,478
- 6
- 16
- 28
If you're logged in to more than one account when you're shutting down, then Ubuntu will take you back to the login screen. You need to log out of each account first, then shut down. (Or at least that's how previous versions worked, I'm assuming it's the same for 12.10 and 13.04).
sudo shutdown -r now
Is a known workaround. (open your terminal and type that + your password)

- 975