After you see "Booting system without full network configuration" press CtrlAltF1. It should get you to the shell prompt. Use a shell text editor to change /etc/network/interfaces.

For example, with nano text editor it would be

sudo nano /etc/network/interfaces

Press CtrlO and CtrlX to save changes and exit nano after you've done with it. (Pressing CtrlX and then N discards changes) sudo reboot restarts the system.

The default contents of the /etc/network/interfaces file look something like this:

# The loopback network interface

auto lo

iface lo inet loopback



# The primary network interface

auto eth0

iface eth0 inet dhcp