I keep "disconnected from xbox live", HELP!

From the last 3 weeks i keep getting disconnected from xbox live even when i play single player (like 3 times a day).

like for example: im playing gears 3 horde mode and im wave 35 and it says disconnected from xbox live, it really pisses me off, my NAT Type is open, i have a fast internet connection, and its wired. is is from my xbox 360 or from the xbox live itself?

The only thing I can say is it may still be your i-net connection. I pay extra just to get the best internet connection but I still get fluctuations where my connection can run like crap. 3 weeks may be a little prolonged for the "fluctuation" theory but it would be worth giving your ISP a call and seeing if they have any other complaints.