Black screen on boot

[AJSlye]

Then grub is not loading the kernel, systemd, etc.
You'll need to rescue the system, the easiest way to do this is with a live media.
You can either use the Maui install ISO, and install (use) the boot-repair tool:

Code:

sudo add-apt-repository -y ppa:yannubuntu/boot-repair; \
sudo apt-get update; \
sudo apt-get install -y --force-yes boot-repair && boot-repair

Or download the boot-repair-tool ISO and create a live USB with it:
https://sourceforge.net/projects/boot-repair-cd/