When you install or upgrade to Ubuntu 12.04, you’ll notice that screensaver has been removed. Now a blank (dark) screen will kick in when your computer is idled. In previous versions of Ubuntu, when your computer becomes idled, a screensaver will start and begin displaying different patterns on your display. Not anymore. If you want to add or enable screensaver package in 12.04, then you must continue below to learn how to do it.
Enable Screensaver in Ubuntu 12.04 (Precise Pangolin)
Enjoy!
To get started, press Ctrl – Alt – T on your keyboard to open terminal. When it opens, run the commands below to remove gnome-screensaver package.
sudo apt-get purge gnome-screensaver
Next, run the commands below to install xscreensaver packages
sudo apt-get install xscreensaver xscreensaver-gl-extra xscreensaver-data-extra
Next, run the commands below to create xscreensaver autostart file.
sudo gedit /etc/xdg/autostart/screensaver.desktop
Then copy and paste the lines into the file and save it.
[Desktop Entry]Name=ScreensaverType=ApplicatonExec=xscreensaver -nosplash
Restart and you’re done. To customize how often it launches, open Dash and search for screensaver, then open it and configure your settings.
Enjoy!

It worked like a charm. Thanks. Newbies (like me), pay attention to the gedit entry. Do it as shown. Line after line.
Sucks – On the second line all I get is
E: Unable to locate package screensaver
:(
After following the instructions Dash could not locate the file “screensaver” for configuration.
Same here…
same here
Thanks!!
how do undo this action? I would like to go back to stock as like before i did the above steps.
Thanks
I did all terminal tasks….
only need to restart and see the magic…
Hope this will work
In the lines to be copied to the file etc/xdg/autostart/screensaver.desktop, the word “Application” was wrongly spelled as “Applicaton”. So that auto restart will not work if it is not corrected..