If turn off firewall, can you ping XP by IP? Or this search result may help,
troubleshooting is not accessible errorTroubleshooting "... is not
accessible" error step by step. When try to access a remote computer, you
may receive the following error messages: ...
Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
How to Setup Windows, Network, VPN & Remote Access on
"JDimick" <JDimick@discussions.microsoft.com> wrote in message
>I am trying to add a Vista computer to an existing home network, but having
> difficulty. The XP computers can see the Vista computer, but not the
> way. Everything appears to be setup correctly, with Netword Discovery set
> On, all the computers on the same Workgroup, etc. Still I cannot map a
> network drive or connect to a network printer on the Vista computer. Any
> ideas would be greatly appreciated. Thanks.