unity not starting auto...so typed unity in terminal...then desktop froze completely...sometimes unity starts but the bar at the top doesn't load...desktop freezes after about 2 seconds

Binary package hint: compiz

desktop freezes all the time

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: compiz-core 1:0.9.2.1+glibmainloop4-0ubuntu7
ProcVersionSignature: Ubuntu 2.6.38-1.28-generic-pae 2.6.38-rc2
Uname: Linux 2.6.38-1-generic-pae i686
Architecture: i386
CrashCounter: 1
DRM.card0.HDMI.A.1:
 status: disconnected
 enabled: disabled
 dpms: On
 modes:
 edid-base64:
DRM.card0.LVDS.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1366x768 1280x720 1152x768 1024x768 800x600 848x480 720x480 640x480
 edid-base64: AP///////wBMo0FUAAAAAAASAQOQIhN4Cof1lFdPjCcnUFQAAAABAQEBAQEBAQEBAQEBAQEBQRxWoFAAFjAwICUAYcYQAAAaQRxWoFAAFjAwICUAWMIQAAAaAAAA/gBDOTcwSoAxNTZBVAogAAAAAAAAAAAAAAAAAAEBCiAgAD4=
DRM.card0.VGA.1:
 status: disconnected
 enabled: disabled
 dpms: On
 modes:
 edid-base64:
Date: Sun Jan 30 15:23:44 2011
DistUpgraded: Yes, recently upgraded Log time: 2011-01-29 13:52:40.988019
DistroCodename: natty
DistroVariant: ubuntu
ExecutablePath: /usr/bin/compiz
GraphicsCard: Subsystem: Dell Device [1028:02be]
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20101202)
MachineType: Dell Inc. Studio 1555
ProcCmdline: compiz --replace
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_IN
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-1-generic-pae root=UUID=01ac361a-bc83-47bb-8f65-abee848fbc04 ro single
SegvAnalysis:
 Segfault happened at: 0xb76de33d <pthread_mutex_lock+29>: mov 0xc(%esi),%edi
 PC (0xb76de33d) ok
 source "0xc(%esi)" (0x0000000f) not located in a known VMA region (needed readable region)!
 destination "%edi" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: compiz
StacktraceTop:
 pthread_mutex_lock () from /lib/libpthread.so.0
 ?? () from /lib/libglib-2.0.so.0
 Glib::Source::unreference() const () from /usr/lib/libglibmm-2.4.so.1
 PrivateScreen::~PrivateScreen() ()
 PrivateScreen::~PrivateScreen() ()
Title: compiz crashed with SIGSEGV in pthread_mutex_lock()
UnitySupportTest:

UserGroups:

dmi.bios.date: 07/03/2009
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A07
dmi.board.name: 0C234M
dmi.board.vendor: Dell Inc.
dmi.board.version: A07
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: A07
dmi.modalias: dmi:bvnDellInc.:bvrA07:bd07/03/2009:svnDellInc.:pnStudio1555:pvrA07:rvnDellInc.:rn0C234M:rvrA07:cvnDellInc.:ct8:cvrA07:
dmi.product.name: Studio 1555
dmi.product.version: A07
dmi.sys.vendor: Dell Inc.
version.libdrm2: libdrm2 2.4.23-1ubuntu3
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10-1ubuntu1
version.xserver-xorg: xserver-xorg 1:7.5+6ubuntu8
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.13.2+git20110124.fadee040-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-1ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu1