Latest version of Firefox of course. Last week or so has been dragging, and eating up all my memory while in use. As a dumb technician, I tried every avenue. Re-installed with a new profile. Of course cleaned her up with all the temp crap, cookies and anything else I could delete that wasn't needed. Cleaned up the entire PC in addition, just in case. I disabled some of my Firefox add-ons, and even deleted some and then re-installed. Upgraded the latest version of Adobe flash player.

I thought all along it was just the latest version causing this, and likely had to wait for the next update. Still pissed me off though, as it sucks to be THAT slow.

So I ran all of my utilities. Then I read something elsewhere - and downloaded 'Malwarebytes' again, which I've used many times but always delete. You only get 15 days for free, so no need to keep it.

It found 1 issue, some 'backdoor agent' in my registry!! I think it was probably the NSA, but who knows.

It seems MUCH faster since, so I'm crossing my fingers!!