I started a Ubuntu install, but the impetuous teenager (IT) at the controls "did stuff" that resulted in an install failure. We had arrived at the partition table. Now, there are no clickable actions in the partition part of the installation. "Install Now" returns the message, "No root file defined." How can I use Ubuntu from CD to make a root file or bootable partition? I've been struggling with the previous screwups by IT for 3-4 days, so I am becoming desperate.