Hi everyone. Wondering if someone can help me out.

The problem I'm having is that I get randomly (or so it would seem) disconnected from Xbox Live when I play MW3. So what usually happens is, I'm halfway through a game, when everything just freezes up until it kicks me from the game. Sometimes this occurs when it tries to change host (whether I am the host in the first place I am unsure), and sometimes simply for no reason at all. I get all sorts of disconnect error messages but the most common one seems to be something about losing connection with the MW3 servers. The one common thing that occurs no matter which error message I get is that I still appear connected to Xbox Live through the X button being pressed (ie. still shows my friends online, messages etc). So I try to search for a new game, and it locks up again. This second time, it will actually disconnect me from Xbox Live itself (not just from the MW3 servers). And then when I try to reconnect to Xbox Live, it won't let me for a minimum of five minutes, and will usually mean I have to reboot the machine if I want to get back online.

The odd thing is, I haven't played MW3 for about 6 months, and when I used to play there were no issues at all. I have not changed any settings on my Xbox and certainly have not changed any in my modem/router. This does not occur with other games. My NAT is OPEN. My Xbox is in the DMZ. I have tried deleting the "title update" and redownloading it, and I have tried clearing the cache on the hard drives - I have even tried both at the same time. It does not help. The only thing I can think of is that something in the "title update" is bugged - because I didn't have a problem before I had to download it.

I have searched google until I think I've read every similar query, but nothing seems to help. I have a D-Link D300 modem/router, and it works fine with up to date firmware etc. Does anybody have any ideas? Any help would be much appreciated.