See:

• http://kb.mozillazine.org/Locked_or_damaged_places.sqlite
• http://kb.mozillazine.org/Lost_bookmarks

If you have used Firefox for more that five days since that loss then you may no longer have a JSON backup to restore the bookmarks from.
If it happened less than five days ago then immediately make a copy of all the .json backups in the the bookmarkbackups folders to prevent losing older copies (Firefox only keeps the last five of the daily JSON backups).

I have a JSON backup. I NEED STEP BY STEP INSTRUCTIONS! Windows XP

I have a saved copy of my bookmarks in my documents. How do I get this file back to my home page?

http://kb.mozillazine.org/Lost_bookmarks#Step-by-step_bookmark_recovery

The file I saved in my documents is labeled JSON. How do I get it back to my home page???

See also:

• http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox

Do you people not understand English?!? Read my post and explain how I do it!!! JEEZ