If you have installed Ubuntu 11.10 (Oneiric Ocelot) or version 11.04 you will need to install a proprietary driver to run Unity 3D rendering if you are using an additional graphics card not supported by the OpenGL graphics. Without a 3D graphics driver Unity will run in 2D mode and you will miss out on all of the awesomeness of the 3D desktop.
To install the latest drivers simply open a terminal window and type the commands below (works with 11.10, 11.04, 10.10, 10.04).
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates sudo apt-get update sudo apt-get install nvidia-current
Step 1. Start a new session of Terminal, then enter the follwoing command.
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
Step 2. After entering the password to execute the sudo command you will need to press enter to continue. The message below will appear prior to pressing enter.
You are about to add the following PPA to your system: Updated versions of X.org drivers, libraries, etc. for Ubuntu. This PPA is for stable upstream releases of X.org components. If you're looking for something even more bleeding-edge, please see the xorg-edgers PPA. While Ubuntu does not "officially/formally" support these packages, if you discover problems when installing these debs please feel free to report bugs to launchpad. However, please make sure to clearly state that you are running packages from this PPA so we know the fixes need to come here. If you are upgrading from one release to another with this PPA activated, please install the ppa-purge package and use it to downgrade everything in here beforehand. sudo ppa-purge ppa:ubuntu-x-swat/x-updates will do it. More info: https://launchpad.net/~ubuntu-x-swat/+archive/x-updates Press [ENTER] to continue or ctrl-c to cancel adding it
Step 3. Ubuntu will now search, download and install the latest proprietary drivers for hardware that requires it. You can later go into the additional drivers manager to enable or disable specific drivers. The below screen is the summary of actions completed in terminal.