Vista hp can't even ping XP - Mike

I added a new OEM Vista Home Prem to my XP Home network ( linksys BEFSR81
router) and I cannot see or file share to the network from the Vista machine.
All XP machines can still share with each other and see the Internet.  The
Vista machine can see the Internet, but not file share.  I can print to the
Vista printer from the XP machines.

From the XP machines, I can CMD-> \\<ip> connect to all XP and Vista
machines.  From the XP machines, I can CMD -> \\<name> connect to the XP
machines, but not Vista.  From Vista, I cannot connect IP or name or ping any
XP machines.  I want to file share.

I have read many messages here and have all the other IP's in the trusted
zones of the Symantic firewalls, all the Windows Firewalls off, have sharing
on all the network shareable drives, and the Vista sharing passwords off.  I
have tried with disabled Firewalls, and with TC/IP6 on and off, all to no
avail.  I had to load IPX/SPX/NetBEUI to my XP machines to file share with
this Linksys (even though TC/IP should have worked?), and that is not
available on Vista.  I even tried to import the XP IPX/SPX protocal files and
manually add to Vista, but lacked digital signatures on the files.

Net Magic works, but Vista should work directly (others have it working).
This seems like a Firewall issue or router issue, but I am out of ideas.
Where should I focus?