Check to see if any of the solutions on the Recover lost or missing Bookmarks page help. It sounds like something probably made Firefox create a new blank profile, which should be pretty easy to fix with the steps in the article.

Hope this helps.

Thank you for ur help. For some unknown reason all is back the way it was.

As long as the problem stays gone. Please flag your last post as Solved Problem as this can help others with similar problems.