I have my desktop receiving wireless internet - the wired NIC is plugged into a separate router (no internet). IPs are configured manually for both the NIC and the 360, and I can ping the 360 from my computer with no problem. The 360 doesn't see the computer (XP Pro).

Ideas?

Have you set up Windows Media Player to share media with the 360?

Yeah the problem is that you need to define "see". Are you looking for the SMB server on the computer? (This is what most people refer to.) The Xbox 360 may not have an SMB client... WMP has the network extender for the 360, so that is what you probably need to turn on and configure.

The 360 cannot see SMB "file" shares. You have to use the Media Sharing functionality of Vista/7 or in Windows Media Player.

I would recommend this.

It won't recognize the computer nor will it pick up an internet connection. Will it be able to access the internet through ICS, or do I have to have it connected directly to the router with the modem?

Uh I think you have to have it directly connected to your router either wirelessly or with a cat5.. Then in WMP11 you can share your library, the zune software shares stuff too. But only WMP11 will share Divx coded videos

It is directly connected to the router, but the router isn't connected to the internet.

Maybe I'll just buy a long cable..

If you figure out what it is, please share it with us. I had a similar issue (XBox 360 hard-wired to network, computer on wireless network). I could intermittently get the 360 to find my PC, but it could never connect to the WMP library share. Only went I put them both hard-wired to the same router did it work.

Connect your Xbox to your PC with an ethernet cable. Bridge your wireless and your hard connection. Open WMP, click the Library menu then Media Sharing, click the Share My Media To box. You don't need the extra router in there.

I would need a crossover cable for that, no? I also have my HD DVD player plugged into the router. That's not necessary, though...and the player is on its way out anyway.

I'm looking for the 360 to get internet more than media, as my TV and sound system can all run from the computer anyway.

You know it might be a problem with the network adapter. After I exchanged my xbox after warranty, brought the new one home and it wouldn't connect to XBox live, had to turn around and take it back the same day.