Question Details:

I just installed Firefox and when I click on the icon this notice came up!! "Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system." I used to have it but uninstalled it of months ago so why is it saying that please?

Answer:

Ending the browser process or restarting the system will normally unlock the profile. If not, see this article for further instructions.