With a wired ethernet or a wireless connection, you do not install a router on every computer!
The install software is necessary ONLY if you use the USB
connection, and then you can only do that for one computer.
On the computer that is not connecting to the router, you need to ensure:
the device is operational and there are no yellow/red flags
go to your Device Mgr and verify Network Adapters.
When connected, the adapter should have a green light next to the cable slot
you used. If not, then the cable is bad or the adapter is not 'active'.