x server is not started

i have installed backtrack 5 but x server is not starting.

The log file /var/log/Xorg.0.log is as follow:

X.Org X Server 1.7.6
Release Date: 2010-03-17
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.24-27-server i686 Ubuntu
Current Operating System: Linux bt 2.6.38 #1 SMP Thu Mar 17 20:52:18 EDT 2011 i686
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.38 root=UUID=416b4011-2876-4afe-8354-d20575367e5c ro text splash nomodeset vga=791
Build Date: 08 March 2011 08:22:50AM
xorg-server 2:1.7.6-2ubuntu7.6 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.16.4
 Before reporting problems, check http://wiki.x.org
 to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
 (++) from command line, (!!) notice, (II) informational,
 (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Fri Mar 16 14:23:57 2012
(==) Using config directory: "/usr/lib/X11/xorg.conf.d"
(==) No Layout section. Using the first Screen section.
(==) No screen section available. Using defaults.
(**) |-->Screen "Default Screen Section" (0)
(**) | |-->Monitor "<default monitor>"
(==) No monitor specified for screen "Default Screen Section".
 Using a default monitor configuration.
(==) Automatically adding devices
(==) Automatically enabling devices
(WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
 Entry deleted from font path.
(WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
 Entry deleted from font path.
(WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
 Entry deleted from font path.
(WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
 Entry deleted from font path.
(WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
 Entry deleted from font path.
(==) FontPath set to:
 /usr/share/fonts/X11/misc,
 /usr/share/fonts/X11/Type1,
 /var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType,
 built-ins
(==) ModulePath set to "/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules"
(II) The server relies on udev to provide the list of input devices.
 If no devices become available, reconfigure udev or disable AutoAddDevices.
(II) Loader magic: 0x81f1e80
(II) Module ABI versions:
 X.Org ANSI C Emulation: 0.4
 X.Org Video Driver: 6.0
 X.Org XInput driver : 7.0
 X.Org Server Extension : 2.0
(--) using VT number 8

(--) PCI:*(0:0:2:0) 8086:0042:103c:304b Intel Corporation Core Processor Integrated Graphics Controller rev 2, Mem @ 0xf0000000/4194304, 0xe0000000/268435456, I/O @ 0x00001170/8
(WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
(II) LoadModule: "extmod"
(II) Loading /usr/lib/xorg/modules/extensions/libextmod.so
(II) Module extmod: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 1.0.0
 Module class: X.Org Server Extension
 ABI class: X.Org Server Extension, version 2.0
(II) Loading extension MIT-SCREEN-SAVER
(II) Loading extension XFree86-VidModeExtension
(II) Loading extension XFree86-DGA
(II) Loading extension DPMS
(II) Loading extension XVideo
(II) Loading extension XVideo-MotionCompensation
(II) Loading extension X-Resource
(II) LoadModule: "dbe"
(II) Loading /usr/lib/xorg/modules/extensions/libdbe.so
(II) Module dbe: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 1.0.0
 Module class: X.Org Server Extension
 ABI class: X.Org Server Extension, version 2.0
(II) Loading extension DOUBLE-BUFFER
(II) LoadModule: "glx"
(II) Loading /usr/lib/xorg/modules/extensions/libglx.so
(II) Module glx: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 1.0.0
 ABI class: X.Org Server Extension, version 2.0
(==) AIGLX enabled
(II) Loading extension GLX
(II) LoadModule: "record"
(II) Loading /usr/lib/xorg/modules/extensions/librecord.so
(II) Module record: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 1.13.0
 Module class: X.Org Server Extension
 ABI class: X.Org Server Extension, version 2.0
(II) Loading extension RECORD
(II) LoadModule: "dri"
(II) Loading /usr/lib/xorg/modules/extensions/libdri.so
(II) Module dri: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 1.0.0
 ABI class: X.Org Server Extension, version 2.0
(II) Loading extension XFree86-DRI
(II) LoadModule: "dri2"
(II) Loading /usr/lib/xorg/modules/extensions/libdri2.so
(II) Module dri2: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 1.1.0
 ABI class: X.Org Server Extension, version 2.0
(II) Loading extension DRI2
(==) Matched intel as autoconfigured driver 0
(==) Matched vesa as autoconfigured driver 1
(==) Matched fbdev as autoconfigured driver 2
(==) Assigned the driver to the xf86ConfigLayout
(II) LoadModule: "intel"
(II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so
(II) Module intel: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 2.9.1
 Module class: X.Org Video Driver
 ABI class: X.Org Video Driver, version 6.0
(II) LoadModule: "vesa"
(II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so
(II) Module vesa: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 2.3.0
 Module class: X.Org Video Driver
 ABI class: X.Org Video Driver, version 6.0
(II) LoadModule: "fbdev"
(II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so
(II) Module fbdev: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 0.4.1
 ABI class: X.Org Video Driver, version 6.0
(II) intel: Driver for Intel Integrated Graphics Chipsets: i810,
 i810-dc100, i810e, i815, i830M, 845G, 852GM/855GM, 865G, 915G,
 E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM, Pineview G,
 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33, GM45,
 4 Series, G45/G43, Q45/Q43, G41, B43, Clarkdale, Arrandale
(II) VESA: driver for VESA chipsets: vesa
(II) FBDEV: driver for framebuffer: fbdev
(II) Primary Device is: PCI 00@00:02:0
(WW) Falling back to old probe method for vesa
(WW) Falling back to old probe method for fbdev
(II) Loading sub module "fbdevhw"
(II) LoadModule: "fbdevhw"
(II) Loading /usr/lib/xorg/modules/linux/libfbdevhw.so
(II) Module fbdevhw: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 0.0.2
 ABI class: X.Org Video Driver, version 6.0
(II) Loading sub module "vgahw"
(II) LoadModule: "vgahw"
(II) Loading /usr/lib/xorg/modules/libvgahw.so
(II) Module vgahw: vendor="X.Org Foundation"
 compiled for 1.7.6, module version = 0.1.0
 ABI class: X.Org Video Driver, version 6.0
(II) Loading sub module "ramdac"
(II) LoadModule: "ramdac"
(II) Module "ramdac" already built-in
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 8, (OK)
drmOpenByBusid: Searching for BusID pci:0000:00:02.0
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 8, (OK)
drmOpenByBusid: drmOpenMinor returns 8
drmOpenByBusid: drmGetBusid reports pci:0000:00:02.0
(II) intel(0): Creating default Display subsection in Screen section
 "Default Screen Section" for depth/fbbpp 24/32
(==) intel(0): Depth 24, (--) framebuffer bpp 32
(==) intel(0): RGB weight 888
(==) intel(0): Default visual is TrueColor
(II) intel(0): Integrated Graphics Chipset: Intel(R) Clarkdale
(--) intel(0): Chipset: "Clarkdale"
(--) intel(0): Linear framebuffer at 0xE0000000
(--) intel(0): IO registers at addr 0xF0000000 size 4194304
(WW) intel(0): libpciaccess reported 0 rom size, guessing 64kB
(II) intel(0): No SDVO device is found in VBT
(II) intel(0): 2 display pipes available.
(II) Loading sub module "ddc"
(II) LoadModule: "ddc"
(II) Module "ddc" already built-in
(II) Loading sub module "i2c"
(II) LoadModule: "i2c"
(II) Module "i2c" already built-in
(II) intel(0): Output VGA has no monitor section
(II) intel(0): EDID for output VGA
(II) intel(0): Output VGA disconnected
(WW) intel(0): No outputs definitely connected, trying again...
(II) intel(0): Output VGA disconnected
(WW) intel(0): Unable to find initial modes
(EE) intel(0): No valid modes.
(II) UnloadModule: "intel"
(II) UnloadModule: "vgahw"
(II) Unloading /usr/lib/xorg/modules/libvgahw.so
(EE) Screen(s) found, but none have a usable configuration.

Fatal server error:
no screens found

Please consult the The X.Org Foundation support
  at http://wiki.x.org
 for help.
Please also check the log file at "/var/log/Xorg.0.log" for additional information.

 ddxSigGiveUp: Closing log