Thanks, fransknorge.

When I go to Tools -> Add-ons and select Plug-ins, there is no Flash and no javascript. Same thing when I select Extensions. (Firefox Help says to disable javascript at Plug-ins. Firefox Help tells me how to add Flash, which I do not believe I have ever done. Certainly there is nothing in Plug-ins or Extensions.) Am I looking in the wrong place? Might it be something else?