I have setup for my internet a westell 6100g modem from verizon and a dlink 615 router .
I keep the router connected because my son brjings his xbox 360 over.
I have showing up in the network map an unknown device.
its between the router and the computer . below is a picture.
if cant view picture looks like this
Your pic isn't showing up, but if its a question mark you may want to unplug your modem and plug it back in, or just go to the modems setting page and restart it that way, at least thats what I do.Sometimes disabling then re-enabling your network adapter will do the trick. Hope I helped