For those of you who live in a mixed household – some Windows XP computers and some Windows Vista computers – getting the Vista systems to share files with their XP brethren can be challenging, if not downright frustrating. In most instances, the problem arises because the Vista systems can’t “see” the XP systems on the network. According to Microsoft “

This problem occurs if the Link-Layer Topology Discovery (LLTD) Responder component is not installed on the Windows XP-based computer.

Network Map in Windows Vista makes network diagrams of the connections between network devices that can be used to troubleshoot connectivity problems. Network Map uses a discovery protocol called Link-Layer Topology Discovery (LLTD) that queries other devices on the network to determine how the network is organized.

A less complex explanation would be that Vista can’t “hear” XP system on the network without the addition of a new louder door bell on the XP systems.

You can find the Microsoft fix to this problem here.