Upgrade from 13.04 to 13.10 has broken my system, no X desktop

[Chris Green]

I just upgraded my system from xubuntu 13.04 to 13.10.

It now just hangs after the login screen.  I enter my password, I get
the screen with the xubuntu mouse in the middle and *no* mouse cursor
and that's it.

Help!  How can I sort this out?  I can login remotely via ssh still and
I can also login via ctrl/alt/<number> so can do things to the system to
fix it - but what do I need to do?

-- 
Chris Green