When does this happen? When you start the browser? While surfing?

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

Tried all kinds of suggested fixes as per https://www.drivereasy.com/knowledge/solved-windows-10-freezes-locks-up-randomly-easily/

Uninstalled and completed a system scan and pc is working fine now.

This has been an ongoing issue since late November - early December. My Windows 10 doesn't like your updates. I've spent way too much time restoring, running checks, uninstalling, re-installing - whatever. I'm done. No more FireFox for me.

After I completed a restore, I used Windows Edge internet browser. No problems. So I downloaded FireFox again. Within no time, my computer froze, and I had to uninstall and try all of the suggestions from https://www.drivereasy.com/knowledge/solved-windows-10-freezes-locks-up-randomly-easily/ After the system check, the problem went away. As I stated before, no more FireFox for me.

Did you uninstall all previous firefox before installing and then deleting the Mozilla folder? Many times I seen this as the culprit to bad install or updates.

Uninstalled Mozilla. Nothing Mozilla or FireFox on pc. Restored. Used Windows Edge for a bit - no issues. Downloaded and installed FireFox again - and voila - screen freezes again.

Why use Restore for that would mean previous firefox with issue would come back.