The router being set to default is no cause for alarm. I remember hitting the reset button thinking it was the power button of the router... Strange that it's so prominent and easily hittable...
Anyway, I started a new thread for this problem
because it doesn't pertain to this new build. I checked my old E8400 system, and also my laptop. Tried them all wired by ethernet. Always the same error as on the new rig, no matter which pc I try.
Took screenshots of t_ski's instruction results... it's all there. Thanks.