This may be easy to answer, but I have no idea...

I have a number of PCs and a handful of servers. The PCs are mostly XP Pro and the servers are all Winows 2003 Server. All of these systems are on (joined to) the same domain. When I go into EXPLORE, some of the sytems see all of the other systems on the domain when I browse through My Network Places, Microsoft Networks, then my domain. Some of the systems can only see some of the other systems out there. A couple, like my laptop, doesn't even have the Microsoft Networks under Network places so I can't browe to the other systems at all. I am logged in to the systems with my account which has Domain Admin rights. Any idea why this is and how I can fix it so that ALL machines will be able to browse in Explorer to all of the other machines? Thanks!!