graphical desktop does not start after install

[Bruno Rebeschini]

I just installed the F8 Unity Re-Spin on an old laptop, but the 
graphical interface does not start.

I used all standard config options to get the desktop installed. Then on 
first boot, I get the config options in text version to deal with 
networking, time settings and so on... but I am not asked to create a 
new user, and I eventually end-up on the command line interface with 
only the root user available.

how can I get the graphical interface to start automatically?