I now have my windows Vista Dektop computer fixed to the point where the firewall is allowing it to see the other computers on my home network. (I had two missing registry files as a result of a nasty virus I contracted some months ago.) The problem is that neither of the other computers -- a mac running OS X and a windows laptop running Windows 8 -- can see the Vista computer, although they can see each other. For example, on the laptop when I click on Network, all I see is the Mac.
I have checked all the settings I can think of and haven't been able to resolve the issue. The Vista computer is running Windows Firewall and Microsoft Essentials. File and printer sharing are allowed and there is a firewall exception to allow file and printer sharing. The homegroup network is set up as Private with no password required. The Windows 8 laptop is unfortunately running Norton since it came preloaded on the computer. But even when I turn off the Norton firewall, it still can't see the Vista computer.