sudo apt-get install network-manager-gnome If there is still no applet in the panel, open the terminal and write: nm-applet
Make sure Network (nm-applet) is set to start automagically in "Session & Startup"
sudo apt-get install network-manager-gnome If there is still no applet in the panel, open the terminal and write: nm-applet
Make sure Network (nm-applet) is set to start automagically in "Session & Startup"