I was really frustrated by this problem. Each time my Windows crashes I lose all my Firefox extensions and themes? I definitely have to come up with something. My regular procedure after re-installing windows is to go the firefox add-ons gallery and search for the extensions and install them one by one. Isn’t it? There is a simple way I came out with, read on.
All the Firefox extensions are compressed and packed in a XPI package. This file can be read by Firefox only. When you click the Install button while installing extensions, Firefox automatically recognizes and runs it, but does not save the XPI file to your computer. So you actually cannot save the extensions in a compact and portable form.
To do so, instead of clicking the install button when on an add-ons page, right click it and select ‘Save Link As’. Select a location and download the file.
A sensible way will be to make a separate folder and backup all your extensions. This way you can install your extensions even when you are not connected to the internet as well as you can send these files to your friends ( in a CD or flash drive )
To install an extension: Open Firefox > File > Open File ( Ctrl + O ). Select your file and push the ok button. The normal install screen will appear.
This is one way. Another way could be that you backup your profiles folder and restore it later on. This will be useful if you want to backup all your settings, extensions, themes etc…
The Profile folder is located here : (in XP)
X:\Documents and Settings\Username\Application Data\Mozilla\Firefox\Profiles\xyxyxyxy.default
When backing up, you will have to replace the original folder with the one you’ve backed up. Although I haven’t tried this method myself, and neither I’m sure it will work. If you know the result, please share with me.
Thanks to techalerts.blogspot.com