Networking

I have an XP based computer and a Vista based computer joined together but they can't see each other on the network map even though both have shared public folders, are in the same work group. In Vista, the network is set as private network so it is expected that devices on the network are discoverable.Is this something to do with the Vista setup? I have connected a crossover cat5 cable between the two computers, give them a fixed IP address each, they still can't see each other. I want the computers to be able to see each other and to map drives for shared directories.