I'm having the same problem. Most of the time I boot my systems, it hangs right after showing the "kubuntu" splash screen and just where it should show the "Nvidia" one.
If I turn off and on again the computer a few times (2 to 10 times), eventually it will boot. I have seen in the Nvidia forum (http://forums.nvidia.com/index.php?showtopic=169294) the suggestion to add the "nopat" kernel parameter in /etc/default/grub: GRUB_CMDLINE_LINUX="nopat" However, I don't know what it means and what side effects that workaround could have in performance or others, or even if that could fix the problem. Somewhere else I have seen the suggestion to remove "splash" from GRUB_CMDLINE_LINUX_DEFAULT. However, I don't know what that means either. Using Ubuntu Natty with all the recent updates. ** Attachment added: "Xorg.5.log" https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/731810/+attachment/1926155/+files/Xorg.5.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/731810 Title: "conflicting memory types" -> "Failed to allocate primary buffer: out of memory" -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs