I have a similar home network without any troubles. But I set it up per our forum sticky at http://forums.cnet.com/5208-7589_102-0.html?forumID=62&threadID=264135&messageID=2584349&tag=forums06;forum-threads
How does your router setup differ from what we suggest?
I have a linksys router which lately has been in the habit of disconnecting one computer (connected throw wireless settings) when the xbox 360 is turned on (and tries to connect to xbox live). I've looked through the web and they say to replace the router but at the moment is not an option. Also, I've seen that they say something about do readdressing on the router ip table, but I'm new at this and I dont know how to exactly assign the xbox a specific static address and have that recognized by the router. In other words.. I know A and B but I dont know how to get from point A to B. Any suggestions will be of great help. Thanks for your time for reading and any suggestions you might have on the matter.