Upfrading from Ubuntu 14.03 to Ubuntu 16.0

[Peter]

I tried to upfrade one of my machines today.It stuck at the point where 
it was asking for acceptance of licencingterms for Microsoft Fonts. I 
clicked on the appropraite button but nothing happened. After 2 hours  
with no progress I killed the machine. On restarting it opens the 
encrypted file system then if goes to temintal session and asks for a 
user name and password. No matter what I enters it keeps asking for the 
same information and the boot does not progress.

Can I revert back to my old version with out losing my home directory?

If so how do I get the new version to install?


Regards

Peter Goggin