Your issue has absolutely nothing to do with Firefox. Your system has other underlying problems, possibly check your hard drive for errors or consult a computer technician.

Let’s do a full clean re-install; Download Firefox For All languages And Systems {web link}

Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86)

Mac: Open the "Applications" folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Do Not remove the profiles folder.

Look for, and rename any Mozilla or Firefox program folders by adding .old to them. Do not rename the Mozilla Thunderbird folder if there is one.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. If all goes well, remove the OLD folders when you are done. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia

The link you have sent me for downloading Firefox in all languages and systems, is a long list of Firefox for various countries. I don't see a version for all languages and systems?

Select the language, and type of system you are using. If you want more than one language, packs are available.

Dowloaded the FF for English Mac OS. I have lots of Mozilla and Firefox folders (maybe 40). Some are called MozillaOrgFirefox2MacOSX2007072517 or with other numbers at the end

Do I have to rename all of these with .old at the end?

Are all of these in the computers Programs Folder? Then yes. By using my instructions (above) any corrupt files should be removed.

Also if the computer is confused about what folder to use, this will keep the computer from finding/using the wrong folder.

None of them come out of a Programs Folder. Also, I do not have a programs folder.

Sorry, Windows: C:\Program Files C:\Program Files (x86)

Mac: Open the "Applications" folder.

There are no folders in the Applications folder called Mozilla or Firefox. Just one Firefox profiles folder.

Then where are these?

NoCombovers said

I have lots of Mozilla and Firefox folders (maybe 40). Some are called MozillaOrgFirefox2MacOSX2007072517 or with other numbers at the end

I called for more help.

They all come from a folder called;

Hard Disk>Users (and then several folders on from there).

What files are in those folders and what is the exact path?

Firefox would normally be installed in /Applications/Firefox.app

Maybe you can attach a Finder screenshot of the parent folder and possibly of the content of one of these folders.

It sounds that there are the permissions or ownership of files or folders, so maybe check that although current MAC OS X versions should do this automatically.

I cannot attach a screen shot because the Mac app for that, called Grab, only saves in tiff format, which is not accepted on this site.

The folders with MozillaOrgFirefox2MacOSX and then a number are mostly like this; Hard Disk>Users>Home Folder>Work>username stuff>user folder>Library>Application Support>FullCircle> then file

Contents (not all have the same); manifest.ini permdata.box Talkback.ini some files with .bun extension (1.bun, 2.bun etc., through to 26.bun) info.db

A half a dozen are like this; Hard Disk>Users>user name>user folder>user folder2>Library>Mozilla

or with various other user named folders in between the Hard Disk and the Library>Mozilla folders

Contents of these; Profiles Application Registry pluginreg.dat

one of the Mozilla folders has an Extensions folder coming from it. In that folder is one file with a long name, of a jumbled up mix of letters and numbers.

EDIT:

The folders named just Firefox have the same paths as the straight Mozilla ones. Contents: Profiles folder Crash Reports folder pluginreg.dat profiles.ini

There is also one folder called Firefox Profiles.

Just chasing on a reply, as its been a while.