Oh! Let me know if you have experienced this.

Try to do this. Go to Mozilla.org or Firefox In Any Language and get the full installer. After you get it, uninstall the current FF. After a reboot, then run the new installer program. Let us know how you did.

Um... I can't uninstall the current Firefox. It shows the same error it does trying to install newer/run FF! I've uploaded a picture of the error.

There may be some changes that haven't been handled yet. Try to reboot the computer one or more times to see if that makes this alert disappear.

You see... I restarted my computer 20 times! And it's still there!

I once had problems with a Windows update. While the install program downloaded, it could not replace the old program with the new. After a LOT of on line and help searching, I discovered that the uninstall file for the old program was missing. Going back to Microsoft help, I found the FIX-IT programs. Once I told FIX-IT what program was giving me problems, that was it. After, I finished the updates. Go to this web page and check it out;
Fix problems that programs cannot be installed or uninstalled

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if that helps to remove the program.

Do a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 26: http://www.mozilla.org/en-US/firefox/all.html

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

• Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you lose personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
• (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other personal data are stored in the Firefox profile folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.

If you keep having problems then also create a new profile.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

Well fredmcd-hotmail, I think that might work. Thanks.

Glad to help. Let us know how you did. Happy Holidays.