Correct. Then reinstalled an older version (62 I think), and all was fine until it auto-updated to v65.

Can you try again, but install Firefox 65.0.1? Dont install an older version.

Tyler Downer said

Do you have any content control software on your computer, such as netnanny? Anything weird? Any registry fixers or optimizers or any sort of security software?

Nope

Can you run these tools https://support.microsoft.com/en-us/help/4026529/windows-10-using-system-file-checker

Tyler Downer said

Can you run these tools https://support.microsoft.com/en-us/help/4026529/windows-10-using-system-file-checker

I have uninstalled FF, where do I get 65.0.1?

Running above next

Go to www.getfirefox.com and download from there. Before you do though, go to program files and remove anything related to Firefox or Mozilla. Then delete your profile in AppData.

Then download Firefox, restart your computer, than install it.

After you run those programs :)

Done, same issue :(

Have you followed all steps at https://support.mozilla.org/kb/firefox-cant-load-websites-other-browsers-can

The "Click the menu button and choose Options" fails to load anything, so stumped at first point in process.

Same issue for the other options.

What was introduced between v62 and v64 that changes the way Firefox works?

Nothing changed that should have broke this, which is weird.

Can you please file a bug at bugzilla.mozilla.org? This will go straight to the developers and they can work to troubleshoot more.

One last thing, Can you try installing Beta or nightly from https://www.mozilla.org/en-US/firefox/channel/desktop/ and see if they work?

Oh, are you using any non-standard themes in Windows?

Tyler Downer said

Nothing changed that should have broke this, which is weird. Can you please file a bug at bugzilla.mozilla.org? This will go straight to the developers and they can work to troubleshoot more. One last thing, Can you try installing Beta or nightly from https://www.mozilla.org/en-US/firefox/channel/desktop/ and see if they work?

Tried both - same issue

Tyler Downer said

Oh, are you using any non-standard themes in Windows?

Nope

Ok, please file a bug describing your computer, setup, and what you are seeing.

I'm exhausted now so maybe tomorrow

Ok, thank you! Once you file the bug report, please paste a link to the report here

Looking at Bugzilla - finally. Did a search for similar bugs....

Not sure why that is any better than here - at least here people use proper English rather than tech shorthand and incomprehensible language.

I do not have a Bugzilla account - seems a little pointless to create a login and log this bug there.

I have reinstalled version 63 and will just stick with that.

JimWUK said

I do not have a Bugzilla account - seems a little pointless to create a login and log this bug there.

The point of posting to Bugzilla is to get the attention of a Mozilla developer and possibly help with your support issue from a developer. This forum is 'staffed' mostly by other Firefox users, and the occasional Mozilla staff person or management type, not by Mozilla professional or developer types who don't "do support" here - that's not what they are paid to do.

I just don't have the energy to waste on this issue.

Resolution: Install v63 and never move beyond on this PC!

Thankyou for all your help.

Gah 63.0.3 autoupdates on installation now even though set to only Install when I choose. So having to go back to 62!