I have ubuntu 12.04 installed on my thinkpad T520, running for a round 1 year. I am not able to shut down my machine even I do: sudo shutdown now. At first, it halts after messages of collectmon signal caught and modem-manager signal cuaght:http://postimg.org/image/j5z02ostj/99e2fcb0/ I uninstalled both programs. Now it halts "my_username login:". If I shutdown right before login, I have this screen:http://postimg.org/image/rs29na4tj/0fcc47f8/, still refuse to shutdown. I suspect it might be a result after I disabled some of the service through boot-up manager. I didn't take notes exactly what I did and neither there were any problems at that moment. I would like to know what prevents the machine to shut down. Now, I have to press the shut down button everytime, which is annoying. This is the screen capture of the services that is still disabled: http://postimg.org/gallery/2miz1zpe/dfe5c337/