Networking problem

Hi,

I have two machines on a hub:

Machine A
----------
This is a Windows 2000 Pro machine with 2 NICs - LAN and
WAN, the WAN card being connected to a DSL router/modem.
This machine can browse the Internet OK. The LAN NIC has
a static IP of 192.168.16.122 and the DNS is dynamic.

Machine B
---------
A new Windows XP Pro machine with 1 NIC - LAN with a
static IP of 192.168.16.123.

What I want to do
----------------
I want to browse the Internet from the XP Pro machine.
The Windows 2000 Pro with dual NIC can browse the Internet
fine.

Ping
----
I can ping a public IP from the Windows 2000 Pro machine
but cannot from the Windows XP machine. I can ping the
Windows 2000 machine from the XP machine, but not Windows
2000 to XP machine.

How can I make the Windows 2000 Pro ping the XP machine
and how do I get the Internet going on the XP Pro
machine. The Win2000 Pro machine can browse the web OK.

Both machines are simply connected to a LAN.

HELP!!!

Skc