hi. i was looking at my network settings today on my pc and noticed a router (linksys wrt160nv2) that wasn't mine. i can right click on it and see its mac address but when i double click it asks me for a pin number. the device shows up with both a wired and wireless connection. i'm using windows 7 64-bit.
An old router or someone else using your network??
I would disable and then delete it.
Check your wireless network security -- use WPA2 and disable WPS. You can also use MAC address security if you think it warranted, although it is a bit of a hassle if you have friends over with laptops/cellphones that connect to your network.