--Close Firefox First---
1. Browse and Navigate to the Hard disk where your Windows is Installed.
2. Then go to the following location C:\Documents and Settings\Username\Application Data\Mozilla\Firefox\Profiles\
3. Inside the Profiles folders you should see a single directory or multiple directories if you are using multiple Firefox Profiles.
Select your Default Firefox Directory.
4. Inside this Directory you will see a folder called “bookmarkbackups” go into this folder.
You will see a bunch of html Files name bookmarks and a date. These are the bookmarks that have been backup for the last five days by Firefox.
5. Select a file that is a day or two older than todays date.
For example today’s date is 2008-10-22 then select bookmarks-2008-10-21.html i.e a file which is a day older.Copy this file and rename it to bookmarks.html
6. Put this file in the main Default profile Directory and replace the old file.
i.e C:\Documents and Settings\Username\Application Data\Mozilla\Firefox\Profiles\stzbt87m.default\
7. Start Firefox.