Despite having a tick next to the "remember what I enter into search bars" box in the options menu, Firefox automatically "forgets" this information whenever I close the browser. I should point out that the information stays up until Firefox is closed and that I haven't accidentally clicked the "clear my private data when I close Firefox" box.
Anyway, I've tried using CCleaner, uninstalling Firefox, Deleting Mozilla Firefox program files, reinstalling Firefox etc., etc.