Let’s do a full clean re-install; '''[http://www.mozilla.org/en-US/firefox/all/ 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.<br>https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac '''Linux:''' Check your user manual. '''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. After rebooting the computer, run a registry scanner. 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 Starting The Computer In Safe Mode;<br>Free Online Encyclopedia]'''