The wall sockets and the RJ45 connector look OK and since you have already mentioned that the other computer works well, it means the problem is rather on the AMD computer's side.
I've forgot to ask if the
Network Adapter is enabled (on the AMD computer)
.
Please
right-click on the start menu, then select
Device Manager and do as in this video (from
0:25) to check:
Let me know if there are any yellow triangles with exclamation sign on them.
You can use Google to search for a
RJ45 loopback plug or you can make yourself one. Buy a RJ45 toolless connector like this one:
and connect the wires as in this image (the blue and the green only, pins 1,2,3 and 6)...