That's supposed to show you the problem isn't Firefox, don't know how successful that actually is. You can delete it so that it starts up again. Susggest restarting Firefox when you see it has used about an hour of CPU time as the next hour of CPU time will take shorter to get there and you will be locked out. Also see this -- the solution on all the items seem to fix a lot of problems with the places.sqlite database. :'''freezing at regular intervals''': http://blog.bonardo.net/2011/09/30/is-your-firefor-freezing-at-regular-intervals