I need to remove GNOME 3, so I can re-install it, for I experienced a huge power surge that disrupted my session in GNOME 3, and currently, the GNOME 3 interface is acting strangely.
sudo apt-get install --reinstall gnome-shell will do the work for you.
Simply enter the following in a terminal to remove Gnome 3:
sudo apt-get remove gnome-shell
...and the following to install it again:
sudo apt-get install gnome-shell
However, you may want to try running
dpkg-reconfigure before attempting a re-install just in case that fixes the issues you are experiencing:
sudo dpkg-reconfigure gnome-shell
1 and 2 provide a simple step by step guide to install Gnome on Ubuntu. However, for the sake of completeness, first of all, remove the current Gnome by
apt purge gnome-shell.
And then reinstall the following packages,
apt install gnome-shell ubuntu-gnome-desktop.
Finally, one more thing is to choose the default graphical interface, for instance, when you are hosting LXDE and Gnome-3 simultaneously on your PC, it will ask for
gdm3 V lightdm.