I've run into this too and can't get around it. When I originally unstalled the 7000 build I was able to connect over IE8, and quickly downloaded firefox. Within a half hour IE8 died, as did my live mesh client, while it was in the process of syncing with my live desktop. Similarly, gadgets that are designed to connect to the internet (weather, feeds, etc) also come back with no connection. I would imagine that at the nexus of these symptoms is the source of the problem. Simply put, I don't think that this is uniquely an IE8 problem, but something a bit deeper in the OS
Yes, I have the most up to date wireless drivers.
The problem persists whether I am wireless or wired.