Comment 5 for bug 672982

1) the system without auto login was recover by going to console & running
- apt-get autoclean ; then -f install ; then -f install kubuntu-desktop
which rolls kde backtop kubuntu 10.10 (4.5.1)

2) the system with the auto login had a clean install of 10.10, and then with a fresh (clean) install the ppa [ppa:kubuntu-ppa] was added and the system upgraded - which then booted to a blank screen once again.

At this point, the cause is unknown

Something in the upgrade causes the X server to crash. I don't know if it's the ppa or kde 5.4.3

Place a recommend in any future kde upgrade notices to turn off auto login.

From my view kde 5.4.3 is DOA