This is because of Optimus and a possible faulty installation of nvidia driver. Please try a clean install and use Bumblebee.
** Changed in: nvidia-graphics-drivers (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to nvidia-graphics-drivers in Ubuntu. https://bugs.launchpad.net/bugs/1085998 Title: Complete system crash after installing ubuntu 12.10 on dell xps 15 (nvidia optimus) Status in “nvidia-graphics-drivers” package in Ubuntu: Invalid Bug description: I installed ubuntu 12.10 on my dell xps 15 (includes a nvidia optimus graphic card), right after the installation (first new start of the system) it crashed complete: is only saw a black screen and one window which reportde: System running in low graphics mode Nothing worked to fix it with system tools To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers/+bug/1085998/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp