Hi. My name is***** you get the message it means Firefox will need to be re-installed.
Before doing that you'll need to remove the current Firefox folder.
Right-click on the start menu button and select Run.
The Run box will open.
In the text area type: c:\program files (x86) and click OK
Right-click on the Mozilla Firefox folder and Delete it.
Then go to www.mozilla.org
click the Firefox tab and then select Firefox for desktop.
Install Firefox and you should be back in business.
Let me know the result please.