My setup is a laptop and and a monitor. I don't know what happened / changed, but now my display is glitchy. It's like the two screens are locked in a mirror mode, but they each have a display partially stacked ontop of eachother. Check out the embedded pictures below.
I've tried:
Playing with the gui display settings.
Xrandr -o normal.
Xrandr -s 0.
Plugging in a different brand monitor (same problem with second monitor)
If this is a recent development, it may be an updated release of the kernel that is not playing nicely with your hardware.
Can you please reboot and select Advanced Options for Zorin from the grub menu (Tap the esc or the tab key at M.B. Splash screen if you need to in order to see the grub menu) and boot from the Earlier Kernel and test.