Very often, your company doesn’t allow you to install a new software on your company computer. For this purpose, Portable Apps is a very interesting website: it contains a lot of free software ready to be used, without any installation process. Moreover, it releases latest version of software very quickly. For example, 1 or 2 days after the launch of Mozilla Firefox 3.0, it was already in Portable Apps.
Most Firefox plugins (“add-ons“) can be installed in the Portable apps version of Firefox, but not all of them. The Adobe Flash plugin is one of the few ones that you can’t install without administrator rights …
Unless your company installed Firefox 2.x on your computer with the Flash plug-in. If it’s the case, you have just to copy two files from the 2.x install to the 3.0 one :
Go to your “old” Firefox plugins directory, for example: C:\Program Files\Mozilla Firefox\plugins\. Then copy these 2 files: NPSWF32.dll and NPSWF32_FlashUtil.exe to your Portable Firefox directory, like: FirefoxPortable\App\firefox\plugins\. Now re-start Firefox 3.0 … Voilà!
Jean-Etienne's blog 