I suspect this is a duplicate of bug #30284. attaching the /var/log/Xorg.0.log file might verify this. Also, is the card PCI- Express, and do you know if specifying the "radeon" driver in the xorg.conf file lets your run an X-windows environment?
-- ATI X800GT detected as X800SE, "ati" driver auto choosed by xorg doesn't work. https://launchpad.net/bugs/25953 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
