NOTE: This also applies to Windows Media Extender on XP MCE and Windows
Media Connect for XP Home/Pro

It appears there is a conflict with the 2 working on the same machine.
Here is my setup and what I have done to come to this conclusion. I
will also go through the troubleshooting steps done on XP Pro since that
is where I first discovered it.

Vista Ultimate RTM

All networks private (it wouldn't turn on unless they were)
ICS is setup to share Dialup connection to network via nVidia On-board
network adapter.
Netgear FA120 network adapter for actual network access.

Visual setup of network (slightly stripped but equivalent)

Vista ------ Router WAN (on-board)
|-------- Router Port 1 (Netgear)

XBox 360 --- Router Port 2
Laptop ----- Wireless Access

Ok. Vista assigns the on-board adapter 192.168.0.1 and anything
requesting a DHCP address from there something along the lines of
192.168.0.x. That's fine. My router hands out ips in the 10.0.0.x
subnet. My Netgear adapter, XBox 360, and Laptop have an ip. My laptop
is able to see the Vista machine and the same is true going the other
way. Vista is able to see the XBox 360 however the same is not true
going back. For some reason The XBox 360 is not able to see the Vista
machine.

Now here is where it gets interesting. Back when I was trying this on
XP Pro here is what I tried.

-- Disabling the Windows Firewall --- No change
-- Ensuring the correct ports are active --- They were fine
-- Adding the ports into ICS --- No change
-- Used a different router (actually a friends) -- No change

Finally I turned off ICS. Bingo! That was where the issue was at.
With ICS on the XBox 360 was unable to see the computer however now it can.

Now then. The same exact thing is happening in Vista! To verify I did
the following.

-- Disabled ICS and disabled the adapter used for ICS (it was marked
Unidentified/Public unless I did so).

Now I was able to get to the machine fine. However once I set both
things back then I can't get to it anymore.

P.S. - Does anyone know the proper channels to go through to resolve
this? I tried to call and let them know about it back when I had XP Pro
installed but they pinned it as a router issue. I eliminated that one
by trying a completely different router (mine is a Netgear and
borderline Xbox 360 compatible but my friends is a Linksys and is on the
compatibility list).

Wow. Well before anyone says this isn't a supported configuration here
is a link to the page that describes it better...

http://www.xbox.com/en-US/support/co...ernalmodem.htm

Oh and they may be aware of the issue... Something to do with UPNP
blocking. It may explain why XBox Live will work but WMC will not in
this setup. Well my laptop can do this once I download the 20MB file
for the setup of Windows Media Extender.