firefox does not start

[Sandy Harris]

Newly installed system, 8.10 64-bit on Core 2 duo box.
Busy adding software, doing updates, etc.

Firefox worked for a while, then got to a state where
if I try to start it, it always says another firefox is
running and I must kill that or restart the computer.

I've tried restatrting and done "ps ax | grep fire",
"ps ax | grep moz" and "ps ax | more" looking
for processes to kill. No joy.

Presmably there's a lock file somewhere that
causes this, but I find nothing under /var/lock
or var/run.

-- 
Sandy Harris,
Quanzhou, Fujian, China