Network Access

Hello to all. I am very new in this forum and i would like to ask a question about networking in mac.
I connect a modem-router with a network cable to a vista pc (hp laptop) and with another network cable from the modem-router to a mac(mac book pro). This is a simple network.
When i open the finder from mac, i am not able to see the vista pc in the left pane of the finder. To see the vista pc, i have to go to the main menu and select the option connect to a server. In this window, if i type smb://the ip of the vista pc, then the finder displays the ip of the vista pc(not the computer name) and if i click on this ip, then i am able to see all the shared folder on the vista pc. Is it possible to tell me why this is happening?
I have an impression, that if i connect the mac to a network with xp computers, then the finder displays automatically all the network computers. Is this problem is related with Vista?

Thanks

It's not a Windows problem as much as it is having no facility for broadcasting the presence of your computers on the network. Bonjour (a networking service that Apple includes with OS X) helps with making network resources more readily visible. You can read about and download Bonjour for Windows here.