When your router is not working there can be several reasons behind this problem:
1. Physical Connection Problem.
2. Internet Connection Problem.
Before doing any troubleshooting steps into your computer, you need to make sure that you are getting internet on your modem. so you need to connect your modem directly to the router and try to access the internet. if you can access the internet from your modem, but can't access the internet from your router. i will suggest you to visit : [https://goo.gl/NptKSQ|why my netgear router has stopped working]