Install NVIDIA propertiary driver on Ubuntu 12.04 from NVIDIA.com

Select correct graphics card driver from form on http://www.nvidia.com/Download/index.aspx?lang=en-us and download driver file. In my case driver file name was NVIDIA-Linux-x86_64-331.79.run

First you may want to remove old NVIDIA drivers installed from repositories. 

$ sudo apt-get auroremove --purge nvidia-*

Next get out of graphics session to terminal with Ctrl + Alt + 1 and login. Turn off lightdm service that runs display manager that starts X servers, user sessions and greeter login screen. Ensure you are in correct runlevel. 

$ sudo service lightgm stop 
$ sudo init 3

Ensure that file is executable and run the installer. 

$sudo chmod +x NVIDIA-Linux-x86_64-331.79.run
$sudo ./NVIDIA-Linux-x86_64-331.79.run

Follow installer instructions, if asked to register with DKMS, if you accept, every time you will install a new kernel, DKMS will automatically take of rebuilding registered kernel modules, if you do not know what it is accept by default. 

In case of complaint about noveau graphics driver or to load after reboot, make sure that in /etc/default/grub line GRUB_CMDLINE_LINUX_DEFAULT contains nomodeset, if not use for example nano $sudo nano /etc/default/grub and modify the line to:

GRUB_CMDLINE_LINUX_DEFAULT=”nomodeset”

$ sudo update-grub
$ sudo reboot

It should work now.

If for some reason .run installation is complaining that nouveau driver should be removed: 

$ sudo apt-get --purge remove xserver-xorg-video-nouveau
$ sudo reboot

To see what driver is installed:

$ sudo lspci -vk | grep nvidia

or 

$ sudo lshw -C video

Uninstalling nvidia driver

$ sudo sh NVIDIA-Linux-x86_64-331.79.run --uninstall