boot - Ubuntu 16.04 No GUI Video After Installing nVidia Driver

I am new to Ubuntu and Linux, but am not new to installing other operating systems and software. I have been attempting to install Ubuntu 16.04 from DVD on a machine with the following hardware:

• ASRock Z170 OC Formula motherboard, with BIOS version P7.40


• Intel Celeron G3900 at 2.8 GHz (NOT overclocked)


• 8 GB DDR4-2133 SDRAM


• TWO nVidia GTX-1070 video cards


• Samsung 850 Pro SSD 512 GB


• Samsung Syncmaster 305T Monitor

Onboard Video and Secure Boot are disabled in BIOS.

When booting from the CD, and when booting the installed Ubuntu, I had to edit the linux command line in Grub to add nomodeset to avoid getting a black screen after the Grub display. The nVidia driver was NOT yet installed initially.

My application requires installation of the native nVidia display drivers. Therefore, I tried installing the nVidia drivers (version 384) through Ubuntu's Additional Drivers application. The installation appeared to proceed normally as far as I could tell. However, upon rebooting, the screen now briefly changes to the Ubuntu login screen background color, then my monitor loses the video signal, and the actual login screen is never displayed.

However, I am able to toggle into terminal mode by using CTRL ALT F1. I then attempted to resolve the above problem by trying various solutions listed at the following links:

Trouble installing Ubuntu 16.04 since I got GTX 1070

My computer boots to a black screen, what options do I have to fix it?

Graphics issues after/while installing Ubuntu 16.04/16.10 with NVIDIA graphics

Blank screen after installing nvidia restricted driver

The most commonly recommended solution in these threads seems to require running the following commands from a terminal session:

sudo apt-get purge nvidia-*
sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt update
sudo apt-get install nvidia-384
sudo reboot

However, following that procedure has not changed my results. I suspect that I am missing some other important step, but can't figure out what it is. Can someone help?

This problem apparently resulted from a defective monitor. While attempting some other solutions, I noted some minor defects in the monitor display (a small section of flickering pixels) that were always present, even in UEFI setup. I switched to a different monitor and reinstalled Ubuntu and the native nVidia drivers without any problems, without even needing to use nomodeset.