Hello Anonymous. Although possibly not related to your problem, I will remind you that the version of Firefox you are using at the moment has been discontinued and is no longer supported. Furthermore, it has known bugs and security problems. I urge you to update to the latest version of Firefox, for maximum stability, performance, security and usability. You can get it for free, as always, at [http://www.getfirefox.com getfirefox.com]. As for restoring your old data, hopefully this support article will help you understand what you should do (should have done): https://support.mozilla.com/en-US/kb/Backing+up+your+information

See: http://kb.mozillazine.org/Lost_bookmarks http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox