It's hard to read all-upper-case text... some people also may interpret it as shouting. We're just volunteers trying to help, so please don't shout at us. If you visit your add-ons list, what is the name of the disabled add-on? There are many different video downloaders and some may have updates that work with Firefox 4. You can check under orange Firefox button > Add-ons (''check Plugins and Extensions'') ''or'' Tools menu > Add-ons (''check Plugins and Extensions'') If you don't find a satisfactory solution, here's the process to roll back: First, I recommend backing up your Firefox settings in case something goes wrong. See [https://support.mozilla.com/en-US/kb/Backing+up+your+information Backing up your information]. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.) Next, download and save Firefox 3.6 to your desktop for future installation. http://www.mozilla.com/firefox/all-older Close Firefox 4. You could install Firefox 3.6 over it (many have reported success) or you could uninstall Firefox first. If you uninstall, do not remove your personal data and settings, just the program. Unless you have installed an incompatible add-on, Firefox 3.6 should pick up where you left off. If there are serious issues, please post back with details. Note: I haven't actually tried this myself!