Yes, I've set up some shared folders to be able to test it.

When I go to My Network Places, on the LAPTOP, for instance, I get three options.
1. Add Network Place - when I browse on this I don't get the option of the other computers, just the Laptop
2. Home Networking Wizard - which I've done several times
3. Entire Network - clicking on this opens Homenetwork, but clicking on that only shows the Laptop, not the other computers.

I'm checking now to see what happens doing the same thing from the other computers.

As to firewalls, I'm using ZA and I believe the XP firewall is running since I installed SP2.