Tips for Troubleshooting Your Internet Connection
The Problem: You buy a new router. You disconnect the old router, connect the new one, and follow the manufacturer's instructions for setup. Even though you can see the new wireless network and can even connect your computer or device, you cannot browse the Internet.
Quick Fix: Unplug the network cable (or cables) and power from the broadband modem you received from your ISP including the coaxial or DSL connection, as well as all cables from the new router. Leave everything unplugged and disconnected for at least 30 seconds. Next, re-connect the coaxial cable, DSL, or FIOS connection to the broadband modem, making sure it's firmly in place and that the WAN/Internet light is on. Then, attach all cables back to your router (including the Ethernet cable from the broadband modem to the router's WAN port) and power the router back on. Make sure the Internet connection activity light is on. Doing these steps forces the broadband modem to flush any information it is holding onto from your previous router. Try browsing the Internet. If you still can't, go through the router setup instructions again, now that you have reset the broadband modem.
Internet Connection Tips; My New Router Won't Connect to the Internet