Weird Session Behavior in Browser

[Tom]

I'm pretty sure this is an unusual case and I suspect it has as much
to do with what the browser is doing as it does PHP on the server, but
the behavior defies anything I would have expected. What happened:

I have a script that depends on sessions to pass some data between
pages. If register_global s is on, the session fails for reasons I've
explained here:

http://phosphorusandlime.blogspot.co...clarified.html

So when I uploaded my script to my host server, register_global s (RG)
was on and the script failed to preserve data. Ok, I turned RG off.
Now what is curious is, after I did this and tried the script again in
my browser (Firefox), the script continued to fail to preserve data.
At first, I figured either it was a delay in the server applying the
new settings or something with caching in my browser. I tried script
again in new browser (IE 7) and everything worked. Tried script on
different computer with Firefox: everything ok.

Now this is what has me baffled:

When I closed Firefox and restarted, the script continued to fail to
preserve session data. Even more baffling, after I completely shut
down my computer, rebooted, and tried again, script *still* failed to
preserve Session data. Continues to this day, only on this browser on
this computer. Meanwhile, other changes to the script/webpage are
reflected.

I'm concluding that it has something to do with the caching in my
Firefox browser. But that doesn't really make sense, since shouldn't
this all be dictated by what's going on server-side? I've looked in
Firefox for a cookie that might be somehow preserving an old setting,
but can't find one.

Anyone know what's really going on here?