windows xp firewall, norton firewall and My Network Places

I had finally got my laptop and my desktop to share files
through My Network Places. And so I thought it would be
nice to have a firewall for protection from viruses. And
so I turned on Norton Firewall(there is a little ikon in
the lower right corner with an X through it until I
activated the firewall). I also found instructions
called "How to enable intenet cdonnection firewall (ICF)
on Windows XP" and turned that on too. Since then, I
can't use My Network Places. Spefifically, I was able to
use Frontpage in my laptop and revise pages on my web
that were located on my desktop. So where are we with
Firewalls and sharing files between computers?
Can you share files and have a firewall at the same time?
How do you set things to do this?
Or do you turn off the firewall in order to share files?
Or what?