And, I am asking a question to whoever had it, because I was under the impression that the installation had to be followed by restart of the browser, as it is done. Sure enough, it closed Firefox, but then I got an error message, telling me that (unnamed)application could not be started because I did not have enough permissions. I did not see anywhere that it needed to restart the system, but, sure enough, I needed to do that to be permitted to open the browser, and use it. Does Adblock Plus do this? Maybe it says somewhere, but it was not a good start. It seems to work ok now, but I was ready to delete the files, if I could not remove it from the browser.