I am forwarding a report from a Ubuntu user.

Ref:https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/229043

"This bug report started as a comment in the thread associated with bug 38915 (https://bugs.launchpad.net/ubuntu/+bug/38915), but as suggested by Sitsofe Wheeler I'm opening a new bug report here.

Problem: 7 out of 10 times my PC freezes when I logout from my Ubuntu session. I get a black screen and my LCD says that there is no video input. Ctrl+Backspace and Ctrl+Alt+Del keyboard salutes don't work, and remote ssh sessions into my machine die; the only way out is a hard reset of my PC. As far as I can say nothing is logged in either the syslog or the X log files.

Environment:
  * Ubuntu 8.04 running on an ASUS P5E-VM mother board with the Intel G35 (3500) chipset and 2 GB of RAM.
  * My home directory is not local but NFS-mounted from another machine running Ubuntu server 8.04.
  * My xorg.conf file is the barebones one created by running "sudo dpkg-reconfigure -phigh xserver-xorg"; it
     has no mention of a specific driver or monitor details; I guess these days everything X-related is found
     dynamically as X takes over.
  * My PC was upgraded from Gutsy to Hardy. While on Gutsy, my video chipset was not well supported, I
     couldn't enable desktop effects for example, but I never experienced these freezes.

Things that I have done include:

1. Booted Hardy with the Feisty kernel. No changes.
2. Created a brand new user with a local home directory (not NFS-mounted) and tried login in and out. No changes.
3. Tried turning off desktop effects. No changes
4. Modified my xorg.conf file to force X to use the VESA driver ... success, no more freezes after logout.

Of course with this last option I get a sub-optimal desktop but this makes me conclude that the problem is X-related. My first call would be to blame the new Intel driver in xorg."

System & Log files : http://launchpadlibrarian.net/14459249/bug-229043.tar.gz