Installing VirtualBox Guest Additions

1. Login as ubuntu;
2. Update your APT database with sudo apt-get update, and typing your password, if requested;
3. Install the latest security updates with sudo apt-get upgrade;
4. Install required packages with sudo apt-get install build-essential module-assistant;
5. Configure your system for building kernel modules by running sudo m-a prepare;
6. Click on Install Guest Additions… from the Devices menu, then choose to browse the content of the CD when requested;
7. Mount the cdrom with "mount /dev/cdrom /media/cdrom";
8. Run sudo ./media/cdrom/VBoxLinuxAdditions.run, and follow the instructions on screen.