Ubuntu 11.10- Проблема завершения работы

Я использую Ubuntu 11.10 с последними обновлениями. С последних двух недель, когда я пытаюсь выключить Ubuntu, некоторые мои ПК замерзают с помощью Ubuntu Normal Shutdown Screen и выключения, нажав кнопку питания на CPU. После перезапуска ubuntu я проверяю syslog, последние записи в сеансе проблем, как показано ниже: -

Feb 19 19:45:41 ubu dbus[582]: [system] Activating service name='org.freedesktop.Accounts' (using servicehelper)
Feb 19 19:45:41 ubu dbus[582]: [system] Successfully activated service 'org.freedesktop.Accounts'
Feb 19 19:45:41 ubu accounts-daemon[986]: started daemon version 0.6.14
Feb 19 19:45:41 ubu anacron[995]: Anacron 2.3 started on 2012-02-19
Feb 19 19:45:41 ubu anacron[995]: Normal exit (0 jobs run)
Feb 19 19:45:41 ubu kernel: [   20.873895] ppdev: user-space parallel port driver
Feb 19 19:45:41 ubu dbus[582]: [system] Activating service name='org.freedesktop.ColorManager' (using servicehelper)
Feb 19 19:45:41 ubu dbus[582]: [system] Successfully activated service 'org.freedesktop.ColorManager'
Feb 19 19:45:42 ubu dbus[582]: [system] Activating service name='org.freedesktop.ConsoleKit' (using servicehelper)
Feb 19 19:45:42 ubu dbus[582]: [system] Successfully activated service 'org.freedesktop.ConsoleKit'
Feb 19 19:45:43 ubu dbus[582]: [system] Activating service name='org.freedesktop.UPower' (using servicehelper)
Feb 19 19:45:43 ubu dbus[582]: [system] Successfully activated service 'org.freedesktop.UPower'
Feb 19 19:45:43 ubu dbus[582]: [system] Activating service name='org.freedesktop.RealtimeKit1' (using servicehelper)
Feb 19 19:45:43 ubu dbus[582]: [system] Successfully activated service 'org.freedesktop.RealtimeKit1'
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Successfully called chroot.
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Successfully dropped privileges.
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Successfully limited resources.
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Running.
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Watchdog thread running.
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Canary thread running.
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Successfully made thread 1218 of process 1218 (n/a) owned by '1000' high priority at nice level -11.
Feb 19 14:15:43 ubu rtkit-daemon[1220]: Supervising 1 threads of 1 processes of 1 users.
Feb 19 14:15:44 ubu rtkit-daemon[1220]: Successfully made thread 1224 of process 1218 (n/a) owned by '1000' RT at priority 5.
Feb 19 14:15:44 ubu rtkit-daemon[1220]: Supervising 2 threads of 1 processes of 1 users.
Feb 19 14:15:44 ubu rtkit-daemon[1220]: Successfully made thread 1225 of process 1218 (n/a) owned by '1000' RT at priority 5.
Feb 19 14:15:44 ubu rtkit-daemon[1220]: Supervising 3 threads of 1 processes of 1 users.
Feb 19 19:45:44 ubu pulseaudio[1218]: [pulseaudio] bluetooth-util.c: Error from RegisterEndpoint reply: org.freedesktop.DBus.Error.UnknownMethod
Feb 19 19:45:44  pulseaudio[1218]: last message repeated 2 times
Feb 19 19:45:44 ubu udev-configure-printer: add /module/lp
Feb 19 19:45:44 ubu udev-configure-printer: Failed to get parent
Feb 19 19:45:44 ubu dbus[582]: [system] Activating service name='org.freedesktop.UDisks' (using servicehelper)
Feb 19 19:45:44 ubu dbus[582]: [system] Successfully activated service 'org.freedesktop.UDisks'
Feb 19 19:45:45 ubu kernel: [   24.846105] EXT4-fs (sda3): re-mounted. Opts: errors=remount-ro,commit=0
Feb 19 19:45:46 ubu kernel: [   25.565376] init: plymouth-stop pre-start process (1338) terminated with status 1
Feb 19 19:45:54 ubu kernel: [   34.004532] init: tty4 main process (822) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.004838] init: tty5 main process (827) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.005119] init: tty2 main process (844) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.005421] init: tty3 main process (845) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.005726] init: tty6 main process (847) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.006287] init: irqbalance main process (873) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.006561] init: cron main process (893) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.007338] init: tty1 main process (1339) killed by TERM signal
Feb 19 19:45:54 ubu kernel: [   34.010115] init: plymouth-upstart-bridge main process (1416) terminated with status 1
Feb 19 19:45:54 ubu kernel: Kernel logging (proc) stopped.
Feb 19 19:45:54 ubu rsyslogd: [origin software="rsyslogd" swVersion="5.8.1" x-pid="574" x-info="http://www.rsyslog.com"] exiting on signal 15.

Я даю команду «sudo shutdown now» в терминале, но экран замораживается с сообщением

* Отключение управления передачей ...... Затем я выдаю команду «sudo poweroff»

на правильное время выключения системы

Как решить моя проблема?