I recently did a
yum update firefox. This caused my FF to be updated to 3.6 from the earlier 3.0.
Very soon i noticed that while browsing certain sites, i was getting logged out from the X server. The FF seemed to crash my X server.
One such site was this: http://wiki.centos.org/HowTos/VNC-Server
A quick google search reveals that this is a known issue with the the video driver.
The solution was to update the CentOS to the latest 5.5.
However, a quick fix can be done,
Add the following line to the ‘Device‘ section of your xorg.conf file (/etc/X11/xorg.conf).
Option "XAANoOffscreenPixmaps" "true"
Restart X by Ctrl-Alt-Backspace
Check out the problem page again.
In some computers it might also be required to add this line too
Option "AccelMethod" "XAA"