Just attempted to install Ubuntu 16.04 beta over 14.04. I have used 14.04 for a couple of years with no issues whatsoever. However during the installation (by download) the new installation froze 2/3 of the way through.
I am using a two hard disc sustem 1x 128g disc running XP and a second x250g running Ubuntu 14.04. Storage no issue.
Now, when I start up and reaching the options page, booting Ubuntu results in a blank screen. No mouse or Keyboard operational.
Reverting to Advanced options I can enter the generic recovery mode
All options tried, Resume, Clean, Failsafe X, FSCK, grub, network, root, System Summary.
If I then go to resume Ubuntu The screen displays white square blocks and lines in between. No mouse or keyboard operational.
Summary, I think I may have damaged the initial 14.04 programme with the part installation of 16.04.
With no keyboard and mouse I am struggling to find a way forward.
I now also have iso discs for 14.04 and 16.04
Hope the forum can help.