How to set up 2nd wireless router to expand wireless range?

Hi, I have one primary wireless router which has 4 ethernet ports, I tried to set up another wireless router in the open area of my home so that I have stronger signals everywhere in the home. On the 2nd router, I had its WAN connected to one of the 4 ethernet ports from the primary router. I checked that ethernet port from the primary router does have internect connecction if I were to hook up my PC directly with it. But when I hook up my PC with one ethernet port out of the second router, even though I saw 100Mbps LAN status lighting on my pc, and there is even IP address showing on my pc by ipconfig, there was however no internect access if I go to a web page! Both of my routers are ActionTec, I also tried D-link as the second router, still no luck.

Any tips to resolve this issue is very much appreciated!

Dear;
If you have connectivity status ok on your computer then check the DNS and network setting and IP setting of your NIC Card