I'm not sure how this started or why it's happening but I just recently downloaded the Mass Effect 3 demo and that was pretty much the start of the issues. I tried playing the multiplayer version of the demo for a while, and every time I would try to join it would prompt me that I need to be signed into XBL to play and when I sign into my account (again) it would come up with an error message saying "Xbox LIVE: Your connection to Xbox LIVE has been lost. Please sign in again." and gives me the options 'OK' and 'Test Connection'. I've tried things like resetting my modem, router and xbox 360. My brother can play in the other room on xbox live and without any problems whatsoever. I can't connect to xbox live while in any game. I can watch videos streaming from the dash (like the preview for the new MW3 content) and everything, so I don't think it's any issue on my end. I've tried to clear cache and that doesn't work. I'm still gold. I haven't been banned or anything ever. And my brothers are playing in the other room just fine.... A little help on how to fix this would be greatly appreciated.