I use Firefox 3.6 or whatever the new version number had minor problem. Go to my computer, click programs, documents and settings, then click administrator then click Mozilla file, then click firefox, then profiles, open ufcn1vcs and look for session store. JS if there delete.
This did not crash computer because I disabled session store.js made read only file and changed file to open in word (right click properties on session store. js) so it could not open. then added to my anti virus program. Rebooted with no problems