Press Ctrl+Alt+T keyboard key combination to open terminal, and then type in:
sudo apt-get purge google-chrome-stable
If you want to disable the google chrome PPA
Type in
/usr/bin/software-properties-gtk --open-tab=1
Untick the box in front of
http://dl.google.com/linux/chrome/deb/Once you disable the PPA, when you run the updates package managers will no longer list google chrome and you will not be able to install it. You will have to re-enable the PPA.