This article describes how to disable and remove unwanted add-ons in Mozilla Firefox. Browser add-ons can sometimes slow down your computer and cause websites to not function and display properly.
Step 1: At the top of the Firefox window, click on the Firefox button (Tools menu in Windows XP)
Step 2: Click “Add-ons”.
Step 3: In the Add-ons Manager tab, select the Extensions or Appearance panel.
Step 4: Select the Add-on that you wish to remove and click “Remove”.