Hmm, does your computer start Firefox automatically? In that case, it's possible that the Refresh feature ran. That creates an Old Firefox Data folder on your desktop. Do you see that folder? If so, please check inside for a semi-randomly-named folder and check inside there for a folder named bookmarkbackups. If you have that, how recent are the backups?

If you have fresh backups, you can "restore" them to Firefox. This article has the steps, and assuming Firefox doesn't see the dated files, you can use "Choose Files" to point Firefox up to your desktop to the Old Firefox Data folder: Restore bookmarks from backup or move them to another computer.

Is that useful?

If not, it's possible that some other program cleaned up Firefox, in which case, I'm not sure what was left. We'll ask you to poke around a bit.

By the way, thank you for sharing your Firefox information. The Question Details > More System Details for your question shows an optional settings file named user.js file in your profile folder (personal settings folder).

Firefox uses the settings in that file at startup to override your saved preferences from the previous session. Unless you created that file yourself, it may contains settings from an add-on or external software. You can check and remove the file using the steps in this article: How to fix preferences that won't save.

Normally Windows hides the .js file extension. To work with files as accurately as possible, I suggest showing all file extensions. This Microsoft support article has the steps: http://windows.microsoft.com/en-us/wi.../show-hide-file-name-extensions.