http://kb.mozillazine.org/Lost_bookmarks#Bookmarks_missing_after_installing_Firefox_2.0_on_Windows_.3F
Bookmarks missing after installing Firefox 2.0 on Windows ?
Quite a number of people using Windows are reporting that their bookmarks are missing after upgrading to Firefox 2.0. This problem is apparently related to the installer not properly exiting all running Firefox processes (bug 357922). In this case, the bookmarks are not lost. To restore the "missing" bookmarks and fix other problems that may be related to the upgrade: Uninstall Firefox, delete the Firefox program folder (usually "C:\Program Files\Mozilla Firefox") and reinstall Firefox 2.0. The bookmarks will be back to normal (you may need to reinstall some added plugins).\
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