I've followed this tutorial (with the following adjustments below) to install v. 331.67 nVidia driver. But get nvidia-settings (NVIDIA X Server Settings) empty... Then, before restart the PC, I make a xorg.conf in the nvidia-settings. The driver make Unity don't start right. So I installed nvidia-331-updates via apt-get and restarted the PC again. After that, the Unity works fine. But the nvidia-settings gets almost empty... Can someone help !?