[ubuntu] No login screen after upgrade from 14.04 to 16.04

Hi,

I have recently upgraded from 14.04 to 16.04 and I no longer have a working installation. Specifically, I can get the system to boot to a terminal by modifying the grub entry to read "nosplash --verbose text" as suggested in the sticky for this forum. I am then able to "use" the system via tty1.

I have tried many of the things which have been suggested by the author of the sticky titled "Graphics resolution- upgrade/Blank screen after reboot" including attempting to stop and restart lightdm and adjusting the gfxmode but nothing has worked so far.

Can someone help me to identify the problem? Where should I look on my system for indications as to what is causing the issue?

Any help or advice would be very much appreciated.

Thanks for your time.