Can't connect to router menu in Win 7 64..

Hi,

Every router including the Wndr 3700, 3800, or 4500 fails to display its menu in full in Windows 7. Weird thing is that it works in a virtual windows xp mode, and my mac notebook so must be netbios or some firewall problem? Thing is it use to work once upon a time but not any more. And this is for every windows 7 64 machine I own (three of them). Its kind of pain. Anyone have ideas what could be causing this? AV software maybe?

Thanks.