Andavari, I notice this in your signature and was wondering exactly what it was and what does it do? Just curious.

Allows you to right click and select the bold texted "Install" option for .XPI archives that are Firefox Add-on's from within Windows Explorer. You can also just double click an .XPI archive to install it. This negates having to run Firefox then browse to an already downloaded and archived add-on to install it. I had created it after doing a clean install of Firefox and realized it was a bit of a pain to manually install them.

Includes an install .reg file, and an uninstall .reg file if you don't like it.

Ok, I am not fully understanding what you mean. Whenever I have had to reinstall firefox, I google the page of the extension i want and then click install. do you mean it adds something so i dont have to do all this? i am not even sure what an .XPI file is.

No. It's for add-ons that you've downloaded to keep and archive for later installation. The XPI files are ZIP archives with a renamed extension. They contain all the contents of an add-on. ZIP software can open them to see what's inside of them.

Edit: Here's Mozilla's description of XPI.

OK I get it. Sweet. Thatll save time after the initial download.