This router is about two years old in constant use but would like to fix if possible.
Is there a reset button in the back. If so hold down 5 seconds with a toothpick.
My netgear is very similar so I just rebooted it. The check mark light came on along with the power light when I first plugged it in. As soon as the signal light started to blink the checkmark light went out. So it is normal for the checkmark to be off I guess. Hope that helps a little
On your wife’s computer, can you tell if she is not receiving a signal or cannot connect (possible password issue)?