Firefox doesn't start

["Adrin Jalali" <adrin jalali gmail com>]

Hi there, since I've updated my firefox I can not start it. It says :
Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.

even when I start it with -safe-mode or -no-remote switches. and
#ps -A | grep firefox
gets no result.

I have these packages :
firefox-3.0-0.beta2.16.nightly20080206.fc9.i386
xulrunner-1.9-0.beta2.16.nightly20080206.fc9.i386

Best,
adrin.