Make sure all computers are in the same workgroup. Also make sure enable NetBIOS over TCP/IP. These troubleshooting may help,

Step by step troubleshooting VISTA sharing
http://www.chicagotech.net/forum1.htm

Vista Troubleshooting Collections
http://www.chicagotech.net/forum1.htm

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
"Bill Fry" <BillFry@discussions.microsoft.com> wrote in message news:450229BE-7ADF-4BBB-B102-F71EDF9EFC24@microsoft.com...
I have 3 PC's, and 2 Notebooks on a home network. I purchased a Vista
Machine and can not see the XP Pro Machines. I have upgraded one machine to
Vista and can see the other Vista machine, but still can not see the XP
Boxes. All have file sharing and all have the same Workgroup Name.

I can ping the machines, just not connect to them.