2010/10/30 Sawrub <luckysharma11@gmail.com>
 The latest firefox.x86_64 [3.6.12-1.fc14] pushed out seems to be
having some issues, have hung my system twice, as of now. Some one
having same issue.

i've seen my f13 system hang several times in the last two weeks, and every time firefox was running and nothing useful in /var/log/messages. may be related.
When one door is closed, another is open.
(Robert Nesta Marley)