Ubuntu 12.04 will not shutdown; it hangs

[mimi314159]

Hi guys,

I'm brand new to the forums! I am running a fresh install of Ubuntu 12.04 LTS, and now my computer will not shutdown with regularity. (Sometimes it shuts down, usually it hangs on the Ubuntu screen with one or no dots colored orange.) Restart seems to work well most of the time (as in that only hung once).

I tried going to the safe mode to start and reboot from there; that seems to shutdown just fine.

From the regular (non-safe) version of 12.04, I tried typing in

sudo shutdown now

and could see that shutdown froze on the error

modem-manager[3672]: <info> ModemManager (version 0.5.2.0) starting...
modem-manager[3676]:  Could not get the system bus.  Make sure the message bus daemon is  running!  Message: Did not receive a reply.  Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
...
modem-manager[3696]: <info> ModemManager (version 0.5.2.0) starting...
modem-manager[3696]: Could not get the system bus.  Make sure the message bus daemon is running!  Message: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory.

This second error repeated 4 times, then stopped.

I used to have Ubuntu 11.10, and it shut down just fine. I'm running this on a Toshiba Satellite computer. Side note--my wifi is also really buggy, and it causes a hard freeze. This has been a persistent problem even on 11.10, so I'm not sure it's relevant, but I thought I'd mention it.

Is there some sort of package I should install? I've run

sudo apt-get update

, so my version should be current. Thanks!