Installing the Gnome Fallback Desktop
GNOME Session Fallback Desktop
If your PC or laptop is struggling to run the Unity Desktop, you may want to consider installing a less resource hungry desktop such as "gnome-session-fallback". The GNOME Session Fallback desktop resembles the classic GNOME 2 style interface which is still very popular on many Linux distributions. To install the "gnome-session-fallback" desktop, simply run the following command from your terminal:
$ sudo apt-get update $ sudo apt-get install gnome-session-fallback
Once the files have installed, you will need to logout of your system so that you can get to the "lightdm login screen".
To switch from using your "Unity" desktop, click on the small Ubuntu icon located to the right hand side of your userid. You should now see a menu appear similar to the one below:
Now select the "GNOME Fallback (No effects)" option. Once selected you can now enter your password in the normal manner to login. If all has gone well you should see the Gnome 2 style desktop: