ubuntu 10.04 boot script finished, but shell or xwindow not shown

After I automate update my ubuntu from 9.10 --> 10.04 , I can not enter in the system, when the start script executed finished. Nothing comes up.

Then I used a boot ISO entered the system, mount the file system, find boot.log, daemon.log and syslog are all normal.

Why exactly this would happen and how can I fix it? I have grub already installed, may I use it to recover my kernel? If can, how to start up it?

The newest situation here's the daemon log.

Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: Found user 'avahi' (UID 105) and group 'avahi' (GID 111).
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: Successfully dropped root privileges.
Apr 20 14:41:02 BJ-IT-Leona init: apport pre-start process (3219) terminated with status 1
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: avahi-daemon 0.6.25 starting up.
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: Successfully called chroot().
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: Successfully dropped remaining capabilities.
Apr 20 14:41:02 BJ-IT-Leona init: apport post-stop process (3230) terminated with status 1
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  starting...
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: No service file found in /etc/avahi/services.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  Trying to start the modem-manager...
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: init!
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: update_system_hostname
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPluginIfupdown: management mode: unmanaged
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: devices added (path: /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/eth0, iface: eth0)
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: device added (path: /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/eth0, iface: eth0): no ifupdown configuration found.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/lo, iface: lo)
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/lo, iface: lo): no ifupdown configuration found.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: end _init.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: Loaded plugin ifupdown: (C) 2008 Canonical Ltd.  To report bugs please use the NetworkManager mailing list.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: Loaded plugin keyfile: (c) 2007 - 2008 Red Hat, Inc.  To report bugs please use the NetworkManager mailing list.
Apr 20 14:41:02 BJ-IT-Leona gdm-binary[3238]: WARNING: Unable to load file '/etc/gdm/custom.conf': No such file or directory
Apr 20 14:41:02 BJ-IT-Leona init: gdm main process (3238) killed by ABRT signal
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  Wireless now enabled by radio killswitch
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: (16638240) ... get_connections.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: (16638240) ... get_connections (managed=false): return empty list.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager:    Ifupdown: get unmanaged devices count: 0
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): carrier is OFF
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): new Ethernet device (driver: 'tg3')
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): exported as /org/freedesktop/NetworkManager/Devices/0
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): now managed
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): device state change: 1 -> 2 (reason 2)
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): bringing up device.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): preparing device.
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  (eth0): deactivating device (reason: 2).
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <WARN>  default_adapter_cb(): bluez error getting default adapter: The name org.bluez was not provided by any .service files
Apr 20 14:41:02 BJ-IT-Leona NetworkManager: <info>  Trying to start the supplicant...
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: Network interface enumeration completed.
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: Registering HINFO record with values 'X86_64'/'LINUX'.
Apr 20 14:41:02 BJ-IT-Leona avahi-daemon[3212]: Server startup complete. Host name is BJ-IT-Leona.local. Local service cookie is 2991573143.
Apr 20 14:41:03 BJ-IT-Leona acpid: client connected from 3399[107:114]
Apr 20 14:41:03 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/vboxnet0, iface: vboxnet0)
Apr 20 14:41:03 BJ-IT-Leona NetworkManager:    SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/vboxnet0, iface: vboxnet0): no ifupdown configuration found.
Apr 20 14:41:03 BJ-IT-Leona NetworkManager: <WARN>  device_creator(): /sys/devices/virtual/net/vboxnet0: couldn't determine device driver; ignoring...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  (eth0): carrier now ON (device state 2)
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  (eth0): device state change: 2 -> 3 (reason 40)
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) starting connection 'Auto eth0'
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  (eth0): device state change: 3 -> 4 (reason 0)
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 1 of 5 (Device Prepare) scheduled...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 1 of 5 (Device Prepare) started...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 2 of 5 (Device Configure) scheduled...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 1 of 5 (Device Prepare) complete.
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 2 of 5 (Device Configure) starting...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  (eth0): device state change: 4 -> 5 (reason 0)
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 2 of 5 (Device Configure) successful.
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 3 of 5 (IP Configure Start) scheduled.
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 2 of 5 (Device Configure) complete.
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 3 of 5 (IP Configure Start) started...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  (eth0): device state change: 5 -> 7 (reason 0)
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 4 of 5 (IP4 Configure Get) scheduled...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 4 of 5 (IP6 Configure Get) scheduled...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 3 of 5 (IP Configure Start) complete.
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 4 of 5 (IP4 Configure Get) started...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 4 of 5 (IP4 Configure Get) complete.
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 4 of 5 (IP6 Configure Get) started...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 5 of 5 (IP Configure Commit) scheduled...
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 4 of 5 (IP6 Configure Get) complete.
Apr 20 14:41:04 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 5 of 5 (IP Configure Commit) started...
Apr 20 14:41:04 BJ-IT-Leona avahi-daemon[3212]: Joining mDNS multicast group on interface eth0.IPv4 with address 172.23.5.249.
Apr 20 14:41:04 BJ-IT-Leona avahi-daemon[3212]: New relevant interface eth0.IPv4 for mDNS.
Apr 20 14:41:04 BJ-IT-Leona avahi-daemon[3212]: Registering new address record for 172.23.5.249 on eth0.IPv4.
Apr 20 14:41:05 BJ-IT-Le开发者_如何转开发ona mysqld_safe: Starting mysqld daemon with databases from /var/lib/mysql
Apr 20 14:41:05 BJ-IT-Leona NetworkManager: <info>  (eth0): device state change: 7 -> 8 (reason 0)
Apr 20 14:41:05 BJ-IT-Leona NetworkManager: <info>  Policy set 'Auto eth0' (eth0) as default for routing and DNS.
Apr 20 14:41:05 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) successful, device activated.
Apr 20 14:41:05 BJ-IT-Leona NetworkManager: <info>  Activation (eth0) Stage 5 of 5 (IP Configure Commit) complete.
Apr 20 14:41:05 BJ-IT-Leona avahi-daemon[3212]: Registering new address record for fe80::223:aeff:fe67:fa0 on eth0.*.
Apr 20 14:43:03 BJ-IT-Leona NetworkManager: <info>  Trying to start the supplicant...
Apr 20 14:45:03 BJ-IT-Leona NetworkManager: <info>  Trying to start the supplicant...
Apr 20 14:47:03 BJ-IT-Leona NetworkManager: <info>  Trying to start the supplicant...

The last NetworkManager "Trying to start the supplicant... " keeps running again and again and it never stop (I leave it alone last night for 8 hours and I get the daemon.log record it.)

What supplicant it trying to start? How can I fix it or just ignoring it ??

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I reinstall the ubuntu . The problem has been gone... But I still don't know what happened...

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Sounds like your iso file has either moved or gotten corrupted. Try to keep your system updated, files trimmed and pkgs purged of what you no longer need.