This question already has an answer here:
I'm a complete stranger with Ubuntu, and i've run into a problem with installing.
What I am trying to do, is to install Ubuntu 13.10 to my old laptop. This laptop has a new hard-drive, that is completely empty. So no Windows or other operating systems to work with.
I'm booting my computer with USB, and it starts normally, but ass I press "Install Now" instead of "Try Ubuntu", then those problems really start. It gives me message "No root file system defined.." etc.
What to do?