I know it sounds stupid & silly what I have said, but here is a simple Test for the router.
Turn off the Router, connect the router to your laptop with an Ethernet Cable.
When you turn on the Router, if it opens up the computers default web browser by it's self.
It will display - connecting and setup router settings .... please wait a few moments...
That is a sure sign that you are not logged in with the username and password the ISP supplied you with to connect to the Internet, and you are using a default connection with limited resources.
If that is the case all you have to do is go to the routers web page login, click on setup Internet connection, follow the directions on screen and type in the username & password when prompted to do so & complete the setup process.
It's only costing you 10 minutes of your time to rule it out