Networking on Vista

[sorapp]

I am confused with the networking support in Vista ( I have Vista Business). Under XP I set up my home network between my 3 computers as a workgroup and easily moved files between all of them. With Vista it is inconsistent. Sometimes I can access files on one or another system in one direction but not in both directions. Other times the capability moves to a different machine. I have a simple workgroup set up with no password protection specified anywhere. I have tried to give unrestricted permissions to all drives on all systems. Clearly I am missing something in my setup. Does anyone know of an info source that explains this without getting into complex business domains etc.?