This is I believe is a Vista issue which I personally have not yet figured. I am having an identical problem on an 'identical' setup. My PC is multibooted with XP Pro, Vista and Linux and works fine with XP running. Since installing Vista though I have had exactly the same issue (Although the XP setup obviously still works fine) so I can discount a router problem. When I find a solution I will let you know but in the meantime if anyone has any suggestions, please post them!