I had a virtually identical problem and went to extreme lengths to get it resolved. Nothing worked. Until Microsoft gave me the solution. Worked for me, it's easy to do and it may work for others as well. As simple and silly as it sounds, the solution that worked for me was to unplug everything, wait a few minutes and plug everything back in. Unplug the computer, router, cable or DSL modem - everything. Do not simple use the ON/OFF switch. You must remove the plugs from the wall sockets. Good luck.
