Just bought apple tv I have it connected wirelessly to my imac, signal strength is max, shows my network in apple tv settings, i see the component in itunes yet it will not update software or let me log in, says it cannot find ID or password. i know they're good cause I successfully tried it several on my imac itunes account. also if i am seeing it as a device in itunes should it not show up in airport utility as a device, when i scan for devices , nothing? 