troubleshooting Xbox 360 and a router is the 360 detects the connection that would mean there is something wrong with the router and it will be considered as a router issue.Just asking dude, are you using the ethernet?
if it going thur wirekess you still have to type in your WEP key or a security key so that you can access it wirelessly and securely
here are some steps you might want to try
Xbox 360 Software Instructions:
7. Turn on your Xbox 360 console.
8. In the System Area, select Network Settings.
9. Select Test Xbox Live Connection. If you are prompted to sign out, select Yes.
* If you have not set your locale on the console, you will be asked to set it. Your locale is the country or region you are connecting to Xbox Live from.
Hardware Instructions (Wireless)
1. Write down your wireless network name (SSID -example 2WIRExxx) and the security key (WEP key)
* If you are using an Xbox 360 Wireless Networking Adapter (sold separately from your system), connect the USB connector to the USB port on the back of the console. Do not use the front USB ports.
5. Turn on your console and wireless device.
* If you have a wireless-to-Ethernet bridge, turn the device on.
* If you have an Xbox 360 Wireless Networking Adapter, the device will turn on with the console.