We are a Dell shop running XP Pro on peer-to-peer networks and are now rolling out Windows 7 Pro workstations and notebooks. Out-of-the-box we are setting sharing, discovery, workgroup; etc. However, some of the Win 7 machines do not see the XP machines in the network and therefore can't use the GUI to map to the various files and resources. You can attach using "Net Use" or right click Computer and "Add a Network Location" or "Map a Drive" as long as you know the full path (ie: \\server\server_share\production\cad\cnc\nested. But you can not see them in the network window to map drive letters to folders. I have researched this issue, visited numerous forums and talked to many other tech's all with the same issue. The conclusion seems to be its a Win 7 problem not being fully addressed since XP is discontinued. So the current thinking appears to be to use Net Use commands in a autoexec.bat file (or if in a Domain in a login script). So to use the latest version of Windows (7) with XP in a peer-to-peer network we need to use DOS commands to automatically map drives. Seriously? PS: MS tech support states they will provide the answer for $250.

http://windows.microsoft.com/is-IS/windows7/What-is-network-discovery Network discovery requires that the DNS Client, Function Discovery Resource Publication, SSDP Discovery, and UPnP Device Host services are started, that network discovery is allowed to communicate through Windows Firewall, and that other firewalls are not interfering with network discovery. I would check the services above to make sure that they are started