aI have a freshly installed Lubuntu 14.04.1 (installed with forcepae option on a laptop with Pentium M processor). The only problem that I have found so far is that I cannot shut-down or restart the laptop. It always continues showing "Lubuntu" and some dots. Pressing Esc it says

wait-for-state stop/waiting
* Stopping rsync daemon rsync                                         [OK]
* Asking all remaining processes to terminate…                        [OK]
* Killing all remaining processes…                                    [fail]
ModemManager [597] :  <info>  Caught signal, shutting down…

ModemManager [597] :  <info>  ModemManager is shut down

nm-dispatcher.action: Could not get the system bus. Make sure the message bus daemon is running!  Message: Did not receive a reply.  Possible causes: 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.
* Deactivating swap…                                                  [OK]
* Will now halt

The cursor remains blinking but the only way to switch it off is to hold the power-off key pressed for some seconds.

I tried sudo shutdown -h now, sudo halt and sudo poweroff resulting in the same problem.

I also tried to add acpi=force in GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" in /etc/default/grub and run sudo update-grub; then, using the taskbar's shot-down button lead to a direct stop of the laptop equal to holding the power-off key pressed for some seconds.

Next I followed the answer http://askubuntu.com/a/202481/288322. Now, I directly receive some messages during shut-down starting

wait-for-state stop/waiting
* Stopping rsync daemon rsync                                         [OK]
* Asking all remaining processes to terminate…                        [OK]
[ 240.944277] INFO: task kworker/0:2:24: block for more than 120 seconds.
[ 240.944461]       Tainted: G S            3.13.0-34-generic #60-Ubuntu
[ 240.944623] "echo 0 > /proc/sys/kernel/hung_tasks_timeout_secs" disables this message.

followed by some more similar lines and then:

* Killing all remaining processes…                                    [fail]
ModemManager [576] :  <info>  Caught signal, shutting down…

nm-dispatcher.action: Caught signal 15, shutting down...
ModemManager [576] :  <info>  ModemManager is shut down

* Deactivating swap…                                                  [OK]
* Will now halt

[ 600.944276] INFO: task kworker/0:2:24: block for more than 120 seconds.
[ 600.944458]       Tainted: G S            3.13.0-34-generic #60-Ubuntu
[ 600.944619] "echo 0 > /proc/sys/kernel/hung_tasks_timeout_secs" disables this message.

Then, nothing more was coming during the next 5 minutes.

If you know where can I find relevant error information, I will be happy to search for them.