Throughout all my attempts at this, I've reset the router, using its reset button, at least a half dozen times to no avail. I've also turned the system off, unplugged the power cables for the router and modem, and waited 10 minutes or longer before powering everything up again.
I've also powered up in different sequences: modem/router/computer, router/modem/computer, computer/modem/router, and computer/router/modem. The end results are all the same.
The problem is: After hooking up the router's WAN port to the modem and its LAN port to the computer's Ethernet card and powering everything up, the LAN Link/Act(tivity) light on the router will not remain on (it blinks a few times and then goes off), so the router's LAN port is not making a connection to the computer's Ethernet card. Without that connection, I don't have an Internet connection and no URL will work in the browser's Address Bar.
The lights for the router's WAN connection to the modem seem to be fine. The router's WAN Link light on and steady and the activity lights on both the router and modem blinking while they chat away with each other.
Possibly the router's LAN port is no longer functioning. Unfortunately, I don't have another system to check that out.
Thanks again for all your help. I do appreciate it.