If a person makes the same mistake a million times, it is still a mistake, no matter how sure they are that it isn't a mistake.
Eliminate error possibilities. Is the router connected correctly? (Here's the million times mistake thing)
I ask this because in another post, the person was plugging their router's "Internet" port to their computer and their internet source to
a switched port. (The port might say "Uplink" rather than "Internet")
Internet source (Cable modem, ADSL modem) goes to the "Internet" port of router (or "Uplink").
Computer goes to a numbered port on router.
You may have it right, nobody here can see your system. If it's right, reset the router and try again. If still no-go, router needs firmware re-load or be tossed.