This is not the normal "black screen"issue and I was shocked to eventually find out why. The normal advice of reconfiguring Xorg didn't work. Even booting into "Recovery Mode" did not help.
Here is the short end of the stick that fixed it:
sudo apt-get install mdm mate-desktop-environment
Yes you got it right, mdm and the mate-desktop-environment / gnome were somehow uninstalled. This must be whe........
#if you have nvidia make sure you install the nvidia-cuda-toolkit so hardware acceleration can be used
wget http://ffmpeg.org/releases/ffmpeg-3.3.2.tar.bz2
tar -jxvf ffmpeg-3.3.2.tar.bz2
cd ffmpeg-3.3.2/
./configure --disable-yasm
install prefix /usr/local
source path ........
# first we need a physical volume which we use the pvcreate tool to create
# I create mine on /dev/sdb3
pvcreate /dev/sdb3
dev_is_mpath: failed to get device for 8:19
Physical volume "/dev/sdb3" successfully created
# pvdisplay shows the newly created volume
pvdisplay
"/dev/sdb3" is a new physical volume of "1.35 TiB"
--- NEW Physical volume ---
PV N........
This is useful for developing a lot of applications, I'm putting it here to keep it handy for myself and hopefully others:
Choose CountryCanadaJapanUnited StatesUnited KingdomAfghanistan........