Xbox 360 wireless adapter flashing green please help?

I've had an elite since February and have been connecting to Live via a laptop. I no longer have access to a laptop so I obtained a wireless n adapter the one that Microsoft puts out specifically for Xbox360. When I plug it in the adapter flashes green. And I cant get it to connect. When I try, it immediately stops and says "Cannot Detect Your Hardware." I HAVE THE LATEST UPDATE so the installation disc is obsolete and will not install the driver because I supposedly already have it. What in the world is wrong? I don't understand and its very frustrating.