|It's very frustrating because I have ethernet ports all over the house, through the walls to connect to the modem but I can't as only one port works. |
The simple solution is to buy a switch with enough ports to accommodate all your connections and connect it to the LAN port on the router.
If you've already bought a router, click on my name above in my response and read my "how-to" guide titled "adding a second router....." and pay attention to the "LAN port to LAN port" scenario as it's the one you'll want to use in your situation.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.