I've install the GNOME desktop with
sudo apt-get install gnome, as instructed here. It is not working properly, as shown below.
First try to restart your GNOME SHELL as follows-
in the run command option enter the letter "r" and hit enter.Your shell will restart.
If this doesn't work,You maight have to reinstall GNOME SHELL.
To remove GNOME SHELL open the terminal and enter the following command-
and then to re-install GNOME SHELL enter the command-
You may also remove and add the GNMOE SHELL/GNOME DESKTOP ENVIRONMENT from the Software Center but the termial use would be better.
Well here is the GUI way to remove GNOME DESKTOP ENVIRONMENT and GNOME SHELL
Let me bring to your notice that the 500Mb you had installed when you installed GNOME was because it included the DEFAULT GNOME APPLICATIONS,ETC
The problem you are facing is actually with GNOME SHELL-The actual component responsible for the GNOME GUI ENVIRONMENT
So you maight not free as much space as you installed.Because you are not Deleting the APPLICATIONS.
Now the procedure-
3 .After the search returns the results,you will see the 1st result as GNOME DESKTOP ENVIRONMENT
Click on the REMOVE Button against it as shown below-
4.After Removeing the ENVIRONMENT add to the search bar SHELL as shown-
5.After the search results are dispalyed,you will get the 1st result as GNOME SHELL as shown-
Click on the REMOVE Button against it.
After this is done,Restart Your computer.
When the log in screen appears,Click on the sessions menu and you will find that all options of the GNOME ENVIRONMENT are absent.
Log in into the available UNITY environment and INSTALL gnome the same way from the SOFTWARE CENTER as you removed it..In place of the REMOVE Button yu will see the INSTALL Button...