Making sure both XP and Vista are on the same workgroup goes some way towards making the PCs get along on your network – but it won't go all the way. A bigger problem you have has to do with the new Windows Vista network map.

The network map is possibly the best addition that Windows Vista has made to networking. To get there, select Control Panel, Network and Internet, Network and Sharing Center, View full map.

The map shows you all the PCs and devices attached to your network – those in your entire network, not just your workgroup. Hover your mouse over any device to view details such as its IP and MAC address. Click a PC to connect to it.

There's a fly in the ointment, though. Vista sometimes finds and maps items but doesn't know what to make of them or where on the network they fit. Nor will Vista give you any information about them if you hover your mouse over them.

The problem is that to discover information about devices, Vista uses a new protocol, called Link Layer Topology Discovery (LLTD). LLTD is built into any Vista PC, which is why they show up properly on the network map. However, LLTD isn't built into Windows XP.

You can fix the problem by downloading and installing the Layer Topology Discovery Responder. This application will enable your XP PC to show up on the network map, with the mouse hover in full working order.

Layer Topology Discovery Responder is here

http://www.microsoft.com/downloads/d...displaylang=en

i got my information from www.pcadvisor.co.uk