Ever since I downloaded 4.0, when I click a link or try to play a video, a notice comes up that I have to download a newer version of Flash Player in order to access the link. This has blocked me from uploading photos, for example, on FaceBook without reverting to the five-photos-at-a-time system that takes forever. I never had this problem before. 4.0, in other words, has reduced the facility of FireFox instead of enhancing it. Is there a way to revert to my old FireFox version to get back what I had?