I have had this problem ever since I downloaded Firefox 3 the first time, my laptop started slowly remembering the settings when changed them back enough times, but my new computer not so much. I've tried pretty much everything suggested on the support forum but nothing has helped, and I've noticed that the prefs.js file actually keeps turning back to read only after I restart the computer. I have tried if the problem would be with the add-ons, but it just seems that a different set of add-ons causes different problems and I'm not willing to delete all of them just because of this. My settings problems include certain settings not saving, Firefox Updated tab opening everytime, saved tabs won't open after restarting computer and certain add-ons forgetting their preferences.