I remember this happened to my husband’s bookmarks with Firefox on our laptop. It was a couple months ago. Trying to remember wht he did to get them back.
This has happened to my daughter in the past on her Firefox profile. I’m not personally aware of anyway to bring them back.... Sorry to tell you that! Maybe someone here knows of a way, but I sure don’t...
There’s a Firefox add-on called Foxmarks. This is a synchronizing program in case you use more than one computer. The bookmarks are stored on a server online that you can access even from a non-Foxmarked computer. Even if you only have one computer, it’s still handy for just such an event.
Your bookmarks are stored in a file in your user profile.
C:\Documents and Settings\username\Application Data\Mozilla\Firefox\Profiles\ramdomcharacters.default\Bookmarks.html
For some reason Firefox loses association with the bookmarks file, and you have to rename the backup bookmarks file from the same directory.
KoRn’s post above is correct.
You have a second option, you can download Mozbackup at http://mozbackup.jasnapaka.com/ and try to see if you can back up the bookmarks if they are still there, then you can restore them to your (accidentally created new profile that has no bookmarks) profile.
Note that firefox bookmarks are written in html , you can open the file in a word processor and edit it as desired.