What to do if Virtualbox won't go full-screen

These are the steps to take if just clicking on "Install Guest Additions" isn't working.

1. Start the Virtualbox instance that you would like to see in full-screen
2. Go to the 'Devices' menu for VirtualBox.
3. Select 'Install Guest Additions'.
4. Open Terminal
5. Navigate to root and then:

> cd media

> cd VBOXADDITIONS_4.1.20_80170 (or whatever your vbox folder is called)
> sudo sh ./VBoxLinuxAdditions.run

6. Wait for update to complete.
7. Once complete, shut down Ubuntu.
8. Restart VirtualBox