I am having the same issue with my xbox disconnecting at irregular intervals of anywhere between 5 and 40 mins. my computer and my laptop are not having any issues with my IP and i have not had any issues in the time i have had it which is only about a month. My xbox live account has been working fine until yesterday 17th March 2012. It is extremely frustrating the only reason i got the xbox 360 was to watch FOXTEL on it for the 2012 AFL season. It has been working fine up until yesterday.