If you replaced your router and configured your new router to have the same SSID and wifi password as the old one, Windows 7 will refuse to connect to the new router. You’ll need to ask Windows 7 to forget the wifi network and start from fresh. Here’s how to remove a wireless network on Windows 7.
Mouse over the network icon on the task bar, i.e., the “bars” icon. Right click, then select Open Networking and Sharing Center.
Click Manage Wireless Networks in the left hand panel