Ok, I have tried before but maybe i missed something so here goes,

For the last couple of months my internet just stops working randomly, it remains connected but all of a sudden it comes up limited connectivity or unknown network, it does not make sense because it works fine and all of a sudden drops out. I have eliminated that it is my computer, and the router because we have run many many tests with different rooms and different computers and it all does the same thing in only my room. My xbox 360 also suffers the same issue when connected to the same port. It is not the router because we bought a new one and it still happens and all the cabling work correctly according to the ISP when they came out to check it. Any suggestions?

How does your 360 connect to internet? If it's bridged through PC then when you turn the xbox off the PC will think it's not connected to the internet for some reason. [This hardly ever happens for me though, I'm just putting it out there as a thought ;p]

It happens with and without the connection bridged.