how to install virtualbox guest additions
# To install Guest additions, go to:
# Devices --> Insert Guest Additions CD Image
# Open Terminal and type in the following:
cd /media/
ls # Find the Guest Addition CD Image directory
cd {Guest Additions CD Image}
sh autorun.sh
sudo reboot
# When the system reboots, go into full-screen mode:
# right control + f
# View --> Full-Screen Mode
# The resulution should now be greater than the default 800x600