This problem gets worse even with upgrades. Maybe I should have mentioned that the ISP where I have to login to view email is Comcast. My extensions are all disabled and I only have two extensions that come with Firefox automatically. I am getting tired of having to use the Task Manager to close out of Firefox windows when they freeze. Something on Comcast displays a message across the top of the windows stating that another window is slowing things down. This seems to happen every other time. Crazy.

This is still happening. When I try to view my email inbox, a yellow bar pops up along the top of the window saying, "A web page is slowing down your browser." Whether one clicks "Stop It" or "Wait," the bar never disappears. What are you running that causes this freezing on that particular site? My ISP is Comcast.

You just upgraded Firefox again; however, the browser shows no improvements. I just wasted much time logging in to view email.

Download a portable version of Firefox which last worked with your institutions website. This frequently occurs because the page/site uses poor or outdated coding practices in scripts or elsewhere, or contains potentially insecure or dangerous errors which are no longer gracefully ignored by modern browsers.

Possibly related: https://bugzilla.mozilla.org/show_bug.cgi?id=1550147

I was giving that suggestion some thought. It seems likely to make already unstable Windows 7 even more unstable.

I'm not sure why your Win7 is unstable, but a portable app doesn't install anything, it just runs all from one folder, self-contained. You can run it from a flash drive. It wouldn't add any issues. If a previously working but portable version doesn't work for your banking needs, you simply delete the folder.

I think that the repairman that just looked at my computer meant that generally Windows 7 is unstable. But based on what you contributed, I will look for the portable version and try it. Thanks.

I just tried it out. The portable version did the same thing as I described in my third post. This caused confusion because the regular Firefox upgraded to Firefox Browser 71.0. The portable one has the same version number. So, I deleted the folder.

A portable version which is same as normally installed versions which do not work for your site is likely not going to work, either. The idea is to find the last version with which you did not have problems, so you can use it for the site which gives you login issues.

https://sourceforge.net/projects/portableapps/files/Mozilla%20Firefox%2C%20Portable%20Ed./

You can find previous versions here. So try, say, 68 if that was the last version with which you did not have login issues. Or try the last ESR version if necessary.

I could not offer much else, other than keep trying a next older version until one works for you. These sorts of things can be idiopathic. It could be a unique combination of your OS and settings + the website + something in firefox. Not so easy so investigate unless one sits down with the system in question.

Best wishes with this, i hope something changes. Browsers have become barely tolerable even when they work well enough, but it is difficult when something odd happens which isn't a problem experienced by a significant number of users that a fix is known.