Assuming your connection is correct, go to "Local Area Conncetion Status", select "Internet Protocol(tcp/ip)"->properties, select "obtain a ip address automatically". restart pc. To configure your router, open your browser, enter the default gateway ip address of your router, and default password( these may be found in the manual of the router), when entered, select "DHCP or obtain an ip automatically". save your setting. Reset power on cable modem and pc. you can check your ip status with "ipconfig/all" in command window. If it doesn't make sense, there must be something wrong. And deselect all options in your "ie->tools->lan setting".

I guess you have done all these since you can access the internet already. If still can't, then it may be your hardware problems.