xbox will not connect with a wired connection.

I have been having issues connecting with a wired connection. When the connection is successful I will be booted off of my account and unable to log back onto it. I have factory reset my xbox, I have reset my router. I have cleared my Mac address. I have
been having this issue for about 1.5 years. it works with the wireless connection every time, but I do not wish to have a wireless connection, because with a wired connection online gaming runs infinitely more smoothly. I have changed routers. I have tried
everything. Even when the connection does "work" with me logged into my account, the xbox will say "all services are available" and still not actually have service. The wired connection works to any other ethernet enabled device. I have had between 10-15 calls
with Microsoft support over the last couple years and have been a loyal customer since the Halo release at midnight November 15, 2001. This is by far the biggest issue I've ever had with my xbox and would really love someone to help. I also just had a 50minute
conversation and the Microsoft tech accidentally hung up. Nooooo.

Please find it in your heart to help a loyal customer. I really just wanna get play some xbox.

:)