Networking MAC and PC via Router

Pirate Dave

This has probably been asked a hundred times before...
I have a Mac Mini and an IBook that both connect to a wireless router without any issues. I also have a Win2000 PC that connects to the router via ethernet. All three computers can access the internet via the router without any issues.
I have been completely unsuccessful in getting any of these three computers to see each other at all.
I have tried to connect to the PC from the MacMini using the Finder>Go. I tried the computer's name, it's IP address (assigned by the router), and it's IP address with the computer's name. Each time I get the same error which says that the MAC can't read it (Error 32, as it turns out). I have tried the same from PC, but it can't see the MAC either. I have turned off the firewalls, and that didn't help.
Can anyone point me in the right direction???
First look in System Preferences/Sharing - are the
Personal File Sharing and Windows Sharing options

To connect from mac to mac: press the command
(apple key) and k keys at the same time or choose
Go>Connect to Server and type in: afp://
(use the ip address of the mac you are connecting to)