How to remove unnecessary Firefox plugins
Plugins are added by third-party applications to Firefox which add some kind of functionality to the browser. While some plugins make good sense, say the Quicktime plugin for instance, some others are not that easily understandable. Why would I need a Microsoft Office plugin for instance ?
You can check the installed plugins by entering about:plugins in the address bar. The list contains all available plugins that are currently loaded in Firefox. Information like the name, location on the hard drive and a short description are available. The description helps to determine if that plugin is actually needed on your system.
My preferred solution for plugins that I (think I) do not need is to create a temporary directory and move all unnecessary plugins into them. This ensures that I can move them back if I should discover that I do need the plugin.
I tried to remove the following plugins temporarily from my system: iTunes Application Detector, Windows Presentation Foundation, RealPlayer Version Plugin, RealPlayer(tm) G2 LiveConnect-Enabled Plug-In (32-bit), Microsoft® DRM, Adobe Reader Plugin and the Microsoft Office plugin.
Some reappeared after a time which surely has something to do with Windows System file protections.
Plugins can basically exist in two locations. One of them is the plugins folder in the Mozilla Firefox directory, the other is a location in the installation folder of the third-party application. You need to refresh the list to see the changes. Some plugins seem to remain even though you refresh the list.

Syahid A. said...
Or you can backup all of them of one by one with FEBE first.