I have same problem too and dnt know what should I do .
I bought a router ( 2600U D-link ) and I configed it several times but the internet light was off. I decided to beckup from my tp-link configuration and restore it in the D-link one. after it I even cant enter to 192.168.1.1 page and shows the web page is not available .
Im sure the problem is with the new router coz with the old one I can connect to the internet.
when I troubleshoot by explorer , It says - ethernet does'nt have a valid ip .