The Tutor had a client this month (2/19) who was getting a "no IP" address on her desktop computer. In English that means no internet access. BUT, the internet was working on another computer also in the house. So, logic says not the router if one worked and the other didn't. Must be the computer... Hmmm. Both computers were wired, though the Tutor tested connecting to the internet wirelessly and it worked on the computer that returned the "no IP" error message. More head scratching. Could be the network adapter in the computer, though the Windows troubleshooter could not identify ANY hardware problem.
Down to the basement we headed where the Verizon FIOS box was located. Both Ethernet cables were securely plugged into the FIOS router. The Tutor moved the Ethernet cable (those thick cables that look like telephone cords but have a fatter plastic connector on each end) for the "no IP" address computer from one of the FIOS ports to another, again, securely plugged in. There happen to be 4 places to plug in an Ethernet cable on a FIOS router.
Up the stairs we went. The desktop computer was back online! Yes, it can be that simple. But WHY the FIOS port became faulty is a question for VERIZON. The client decided not to call Verizon since we had a solution. So... it WAS a router problem after all.
ALWAYS REMEMBER: before calling for help - is it plugged in, and is it turned on?