Try to switch temporarily to gdm by modifiy /etc/X11/default-display- manager file and see what happens. When you added agpgart module to blacklist file, did you check with lsmod if it was blacklisted correctly?
-- Gnome 2.16 crashes after loading some apps https://launchpad.net/bugs/65971 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
