Can you explain a little bit more? or am I getting this right?
You are connecting your pc to the internet with a ADSL modem (Via USB), and
have a ethernet port on the back of your machine, and a PCI Wireless card in
your machine pumping out a wireless signal? or are you connecting a Wireless
access point to your machine using the ethernet port, and trying to connect
the Xbox up wirelessly?
I'll explain my setup, I have a router with a wireless access point
attached, and I hard-connect my Xbox to the router (saves any chances of
loosing the signal) and I use my wireless access point for any wireless
requirements.
When I had my router set up, I have an IP address of 192.168.1.2 for the
router, and all other machine have 192.168.1.x (x being random) but all the
pc's connect to the default gateway (on the internet properites) of
198.168.1.2 and I set up the primary DNS of 192.168.1.2 which is the router
too. Basically what you need to be telling the Xbox is the IP address you
are wanting it to connect to the internet through, as the Xbox will have
it's own IP, allocated by the DCHP, or if you manually set one up.
DNS Short for Domain Name System (or Service or Server), an Internet service
that translates domain names into IP addresses. Because domain names are
alphabetic, they're easier to remember. The Internet however, is really
based on IP Addresses. Every time you use a domain name, therefore, a DNS
service must translate the name into the corresponding IP address. For
example, the domain name
www.example.com might translate to 198.105.232.4.
The DNS system is, in fact, its own network. If one DNS server doesn't know
how to translate a particular domain name, it asks another one, and so on,
until the correct IP address is returned.
I hope any of this information might help you get your XBOX online, as I
know I had a problem the first time I tried to setup and i found it
annoying...
P.s. I don't know if Xbox does support wireless links though, as when I
first went down that route they didn't advise it....
Regards.