Even when not on intrnet firefox keeps running in the background slows everything down and cannot be uninstalled as itis still running
Sounds like Firefox is "hanging at exit". That problem is frequently caused by an Extension or a Plugin. Read all of the following articles.
NOTE: Establish a habit of exiting/closing Firefox with Firefox button > Exit or File > Exit to allow an orderly shutdown of Firefox and closing of all of the files that Firefox has open.
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Not related to your question, but...
You may need to update some plug-ins. Check your plug-ins and update as necessary: