Please read this article to see if it helps:

http://support.mozilla.com/en-US/kb/preferences%20are%20not%20saved

I had no of the opposing programs installed. However, moving on, most of the proposed solutions couldn't work because the files/items that were said to be going to appear didn't. All I could find was prefs (the final solution), so I deleted it. It appears to have left all my settings untouched. If they stay that way remains to be seen. Thanks for trying. But I still think Firefox 4 was launched prematurely. I'm very disappointed with its instability. And I shouldn't have to be fiddling with it to make it work. It should work, full stop, like Chrome...