Hold down the Shift key when starting Firefox to see if it will work in Troubleshoot Mode.

No still the same.

Try rebooting in Windows Safe Mode with networking enabled.

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

If the new profile works, you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Rebooting in safe mode the problem was still there.

Re creating a new profile. I have totally uninstalled with revo including all the bits left over and reinstalled.

Wouldn't that be as good as a new profile? I have no settings I wish to keep as I'm just reinstalling after aa windows reinstall.

Try reinstalling the Visual C++ Redistributable.

Anything in the Windows Event Viewer log ?

Hold down the Shift key when starting Firefox to see if it will work in Troubleshoot Mode.

Still the same.

What version of Firefox does this happen with?

Are you able to visit about:third-party in the address bar and disable third-party modules?

1 3rd part module: mdnsNSP.dll

Version 120.0.1 64bit

I have just noticed it only freezes when I go to settings>bookmarks

Try installing Firefox from the Microsoft Store and see if it behaves any differently.

Run the System File Checker tool:

sfc /scannow