[MovedGoalPosts]

We are a UK based forum familiar with the UK cable based networks. There probably aren't many differences to the setups "over the pond" but who knows?

When swapping whatever is connected to the modem, you normally have to power the modem off, else it cannot "see" whatever the new device is directly connected.

Make sure your network card settings and borwser are set with everything auto, rather than having any fixed IP or whatever. If you have a firewall on the PC, turn it off for now, while you try for a connection, you can always get it back later.