If Firefox will not start it is probably because the lockfiles weren't cleaned up

# killall -9 firefox
# /panfs/panasas1/system/sysfiles/usrcommon/scripts/cleanFirefox.sh
# /panfs/panasas1/system/sysfiles/usrcommon/scripts/cleanThunderbird.sh

Useful firefox options

firefox -P
firefox -no-remote
firefox -safe-mode