it just lost your bookmarks? is there anything that happened that might be related to that? i've never had anything like that happen to my firefox, and i've been using it for about seven or eight months now.

do you have any extensions installed? if an extension is buggy, it can interfere with the rest of the browser's behavior. one extension messed with my popup blocker.. i went to the extension homepage and saw a big message saying something like "do not use this extensions, it's full of bugs".. so i disabled it and the problems went away.