I've got exactly the same problem. I can disable my Local Area Connection, but if I do I can't enable it again in the same session. I just get a 'Connection failed!' message. If I turn off or attempt to restart my computer just hangs and I have to press the restart button. When I power up again my Local Area Connection is active and if I shut down without disabling it the shutdown progresses normally. I have tried System Restore and reloading my Network Adapter drivers but to no effect. It is an annoying problem and any remedy that falls short of a full format and reload of Windows would be hugely appreciated.