Could this be a compiz problem, causing the X server to crash? Your card should have been blacklisted for compiz though. Can you please try to get some log files, like Xorg.0.log? One way would be to boot with "safe graphics mode", then switch to a console:
sudo /etc/init.d/gdm stop # to stop gdm from restarting
sudo vi /etc/X11/xorg.conf # and change to "ati" driver
startx # to try starting Xorg, which might die
cp /var/log/Xorg.0.log ~/Desktop/ati.log
sudo vi /etc/X11/xorg.conf # and change back to "vesa" driver
sudo /etc/init.d/gdm start # login in again and send the log to us
(I vaguely remember an issue with the gdm init script failing to stop gdm on the live CD. Maybe you have to just kill it.)
Could this be a compiz problem, causing the X server to crash? Your card should have been blacklisted for compiz though. Can you please try to get some log files, like Xorg.0.log? One way would be to boot with "safe graphics mode", then switch to a console:
sudo /etc/init.d/gdm stop # to stop gdm from restarting
sudo vi /etc/X11/xorg.conf # and change to "ati" driver
startx # to try starting Xorg, which might die
cp /var/log/Xorg.0.log ~/Desktop/ati.log
sudo vi /etc/X11/xorg.conf # and change back to "vesa" driver
sudo /etc/init.d/gdm start # login in again and send the log to us
(I vaguely remember an issue with the gdm init script failing to stop gdm on the live CD. Maybe you have to just kill it.)