The problem is, I could log in under the terminal, i could ifup eth0, i could do anything I want in the terminal, but if I use ctrl+alt+f7 goto the gnome login screen, after I input the correct password, the system just send me back to same login screen again.

I have created a new user, but it didn't work.

I have change all the files under ~/ to jichao:jichao(which is my username) with chown -hR jichao:jichao /home/jichao, but it didn't work too.

I searched the internet, somebody said I should see the logs under /var/log/gdm, but there is not a /var/log/gdm directory in my box.

Here are the tail of files under /var/log/

tail X.org.log
[  3263.348] (II) Loading /usr/lib/xorg/modules/input/evdev_drv.so
[  3263.348] (**) Dell Dell USB Keyboard: always reports core events
[  3263.348] (**) Dell Dell USB Keyboard: Device: "/dev/input/event5"
[  3263.348] (--) Dell Dell USB Keyboard: Found keys
[  3263.348] (II) Dell Dell USB Keyboard: Configuring as keyboard
[  3263.348] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/input/input29/event5"
[  3263.348] (II) XINPUT: Adding extended input device "Dell Dell USB Keyboard" (type: KEYBOARD)
[  3263.348] (**) Option "xkb_rules" "evdev"
[  3263.348] (**) Option "xkb_model" "pc105"
[  3263.348] (**) Option "xkb_layout" "us"

kern.log
Mar 20 09:32:58 jichao-MS-730 kernel: [ 3182.701247] input: Dell Dell USB Keyboard as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/input/input27
Mar 20 09:32:58 jichao-MS-730 kernel: [ 3182.701392] generic-usb 0003:413C:2003.0018: input,hidraw1: USB HID v1.10 Keyboard [Dell Dell USB Keyboard] on usb-0000:00:1d.0-1.4/input0
Mar 20 09:33:02 jichao-MS-730 kernel: [ 3186.642572] usb 2-1.3: new low speed USB device number 17 using ehci_hcd
Mar 20 09:33:02 jichao-MS-730 kernel: [ 3186.741892] input: Microsoft Microsoft 5-Button Mouse with IntelliEye(TM) as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.3/2-1.3:1.0/input/input28
Mar 20 09:33:02 jichao-MS-730 kernel: [ 3186.742080] generic-usb 0003:045E:0047.0019: input,hidraw2: USB HID v1.10 Mouse [Microsoft Microsoft 5-Button Mouse with IntelliEye(TM)] on usb-0000:00:1d.0-1.3/input0
Mar 20 09:33:27 jichao-MS-730 kernel: [ 3212.473901] usb 2-1.3: USB disconnect, device number 17
Mar 20 09:33:28 jichao-MS-730 kernel: [ 3212.702031] usb 2-1.4: USB disconnect, device number 16
Mar 20 09:34:08 jichao-MS-730 kernel: [ 3253.022655] usb 2-1.4: new low speed USB device number 18 using ehci_hcd
Mar 20 09:34:08 jichao-MS-730 kernel: [ 3253.124278] input: Dell Dell USB Keyboard as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/input/input29
Mar 20 09:34:08 jichao-MS-730 kernel: [ 3253.124423] generic-usb 0003:413C:2003.001A: input,hidraw1: USB HID v1.10 Keyboard [Dell Dell USB Keyboard] on usb-0000:00:1d.0-1.4/input0
Mar 20 09:33:02 jichao-MS-730 kernel: [ 3186.741892] input: Microsoft Microsoft 5-Button Mouse with IntelliEye(TM) as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.3/2-1.3:1.0/input/input28
Mar 20 09:33:02 jichao-MS-730 kernel: [ 3186.742080] generic-usb 0003:045E:0047.0019: input,hidraw2: USB HID v1.10 Mouse [Microsoft Microsoft 5-Button Mouse with IntelliEye(TM)] on usb-0000:00:1d.0-1.3/input0

syslog
Mar 20 09:33:02 jichao-MS-730 mtp-probe: bus: 2, device: 17 was not an MTP device
Mar 20 09:33:27 jichao-MS-730 kernel: [ 3212.473901] usb 2-1.3: USB disconnect, device number 17
Mar 20 09:33:28 jichao-MS-730 kernel: [ 3212.702031] usb 2-1.4: USB disconnect, device number 16
Mar 20 09:34:08 jichao-MS-730 kernel: [ 3253.022655] usb 2-1.4: new low speed USB device number 18 using ehci_hcd
Mar 20 09:34:08 jichao-MS-730 mtp-probe: checking bus 2, device 18: "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4"
Mar 20 09:34:08 jichao-MS-730 mtp-probe: bus: 2, device: 18 was not an MTP device
Mar 20 09:34:08 jichao-MS-730 kernel: [ 3253.124278] input: Dell Dell USB Keyboard as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/input/input29
Mar 20 09:34:08 jichao-MS-730 kernel: [ 3253.124423] generic-usb 0003:413C:2003.001A: input,hidraw1: USB HID v1.10 Keyboard [Dell Dell USB Keyboard] on usb-0000:00:1d.0-1.4/input0

auth.log
Mar 20 09:18:52 jichao-MS-730 lightdm: pam_ck_connector(lightdm-autologin:session): nox11 mode, ignoring PAM_TTY :0
Mar 20 09:18:53 jichao-MS-730 lightdm: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "jichao"
Mar 20 09:18:53 jichao-MS-730 dbus[835]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.240" (uid=104 pid=6457 comm="/usr/lib/indicator-datetime/indicator-datetime-ser") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination=":1.11" (uid=0 pid=1156 comm="/usr/sbin/console-kit-daemon --no-daemon ")
Mar 20 09:19:38 jichao-MS-730 sudo:   jichao : TTY=tty6 ; PWD=/home ; USER=root ; COMMAND=/bin/chown -hR jichao:jichao jicha
Mar 20 09:19:39 jichao-MS-730 sudo:   jichao : TTY=tty6 ; PWD=/home ; USER=root ; COMMAND=/bin/chown -hR jichao:jichao jichao
Mar 20 09:20:10 jichao-MS-730 lightdm: pam_unix(lightdm-autologin:session): session closed for user lightdm
Mar 20 09:20:11 jichao-MS-730 lightdm: pam_unix(lightdm-autologin:session): session opened for user lightdm by (uid=0)
Mar 20 09:20:11 jichao-MS-730 lightdm: pam_ck_connector(lightdm-autologin:session): nox11 mode, ignoring PAM_TTY :0
Mar 20 09:20:12 jichao-MS-730 lightdm: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "jichao"
Mar 20 09:20:12 jichao-MS-730 dbus[835]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.247" (uid=104 pid=6572 comm="/usr/lib/indicator-datetime/indicator-datetime-ser") interface="org.freedesktop.DBus.Properties" member="GetAll" error name="(unset)" requested_reply="0" destination=":1.11" (uid=0 pid=1156 comm="/usr/sbin/console-kit-daemon --no-daemon ")

It seems that my .xsession-errors does not grow since yesterday. Here is my .xsession-error:

(gnome-settings-daemon:1550): Gdk-WARNING **: The program 'gnome-settings-daemon' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 26702 error_code 3 request_code 2 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)


(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed

(nautilus:3106): GLib-GObject-CRITICAL **: g_value_get_object: assertion `G_VALUE_HOLDS_OBJECT (value)' failed
WARN  2012-03-17 19:28:46 glib <unknown>:0 Unable to fetch children: Method "Children" with signature "" on interface "org.ayatana.bamf.view" doesn't exist


WARN  2012-03-17 19:28:46 glib <unknown>:0 Unable to fetch children: Method "Children" with signature "" on interface "org.ayatana.bamf.view" doesn't exist



(yunio:2430): Gtk-WARNING **: ??????????????:“pixmap”,

(yunio:2430): Gtk-WARNING **: ??????????????:“pixmap”,

(polkit-gnome-authentication-agent-1:1601): Gtk-WARNING **: ??????????????:“pixmap”,

(yunio:2430): Gtk-WARNING **: ??????????????:“pixmap”,

(yunio:2430): Gtk-WARNING **: ??????????????:“pixmap”,

(polkit-gnome-authentication-agent-1:1601): Gtk-WARNING **: ??????????????:“pixmap”,

(polkit-gnome-authentication-agent-1:1601): Gtk-WARNING **: ??????????????:“pixmap”,

(polkit-gnome-authentication-agent-1:1601): Gtk-WARNING **: ??????????????:“pixmap”,
/usr/share/system-config-printer/applet.py:336: GtkWarning: ??????????????:“pixmap”,
  self.loop.run ()

(unity-window-decorator:1652): Gtk-WARNING **: ??????????????:“pixmap”,

(unity-window-decorator:1652): Gtk-WARNING **: ??????????????:“pixmap”,

(unity-window-decorator:1652): Gtk-WARNING **: ??????????????:“pixmap”,

(unity-window-decorator:1652): Gtk-WARNING **: ??????????????:“pixmap”,
common-plugin-Message: checking whether we have a device for 4: yes
common-plugin-Message: checking whether we have a device for 5: yes
common-plugin-Message: checking whether we have a device for 6: yes
common-plugin-Message: checking whether we have a device for 7: yes
common-plugin-Message: checking whether we have a device for 10: yes
common-plugin-Message: checking whether we have a device for 8: yes
common-plugin-Message: checking whether we have a device for 9: yes

(gnome-settings-daemon:13791): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed
[1331983727,000,xklavier.c:xkl_engine_start_listen/]    The backend does not require manual layout management - but it is provided by the application
** (gnome-fallback-mount-helper:1584): DEBUG: ConsoleKit session is active 0

(gnome-fallback-mount-helper:1584): Gdk-WARNING **: gnome-fallback-mount-helper: Fatal IO error 11 (???????) on X server :0.


(gdu-notification-daemon:1708): Gdk-WARNING **: gdu-notification-daemon: Fatal IO error 11 (???????) on X server :0.

unity-window-decorator: Fatal IO error 11 (???????) on X server :0.0.

(bluetooth-applet:1583): Gdk-WARNING **: bluetooth-applet: Fatal IO error 11 (???????) on X server :0.


(nm-applet:1596): Gdk-WARNING **: nm-applet: Fatal IO error 11 (???????) on X server :0.


(nautilus:3106): IBUS-WARNING **: _connection_closed_cb: Underlying GIOStream returned 0 bytes on an async read

(update-notifier:1821): Gdk-WARNING **: update-notifier: Fatal IO error 11 (???????) on X server :0.

applet.py: Fatal IO error 11 (???????) on X server :0.

(nautilus:3106): Gdk-WARNING **: nautilus: Fatal IO error 11 (???????) on X server :0.

Could you help me, Thanks.