So, nomodeset doesn't seem to be the trick - which makes me think maybe a kernel related issue..
As you're booting, if it's using BIOS to boot hold 'Shift' - if it's UEFI hold 'Esc' - once you bring the Grub menu up, go down to Advanced Startup Options, then drop to a root shell (instructions here: [HOW TO] enter Recovery Grub Menu (Advanced Options for Zorin)).
Now, you'll be asked for authentication, enter your root password - then proceed to once again enter: nano /etc/default/grub, then remove the 'nomodeset' so that only "quiet splash" is showing. Do Ctrl+O to write the changes, then Ctrl+X to exit, then sudo update-grub, reboot - and you should be back to a booting machine - but with the remaining freezing..
Once you have a bootable machine again, I'll do more investigating to try and see what's going on with freezing..