Vista and XP machine network issues

I had 2 XP machines hooked up to a router and ADSL internet
connection.

Since replacing one of the XP machines with a VISTA 64 machine (not an
upgrade), I am seeing some network issues. There were no problems
with network or internet connections when there were just 2 XP
machines connected to the router.

Now:
Both machines (XP machine and VISTA machine) are in the same
workgroup.
Both machines can ping each other
There is a printer connected to the XP machine, the VISTA machine can
use that printer through the network.

Issue #1 (XP machine does not show up in the network view of the VISTA
machine)
1) XP machine can see the vista machine in network view
2) VISTA machine can see the XP machine for a couple seconds when
first entering the network view then the XP machine does not not show
up anymore within the VISTA network view.

I would like to be able to see the XP machine and shares from the
VISTA machine.


Issue #2 (VISTA machine is limiting the internet access to the XP
machine)
1) If the VISTA machine goes into sleep mode the XP machine loses the
internet connection
2) If the VISTA machine reboots, the XP machine will lose internet
connection while the VISTA machine is booting

Somehow the VISTA machine is controlling the internet connection, how
can this "control" be removed. I don't want the VISTA machine status
to effect the internet connection of the XP machine. Is the VISTA
machine taking control of the router somehow when it is on ? For
example with the VISTA in sleep mode and the XP machine cannot access
the internet, if I unplug the LAN cable from the sleeping VISTA
machine then the XP machine can access the internet.

Thanks for any help !