Ok log into your router via a cable connection.
Simply put the gateway address of the router into your browser as an address 192.168.0.1 or 192.168.1.1.
Once logged into the router, make sure Dhcp is enabled, and that the upnp option is enabled in the router one of the router sub menus. save the changes made before exiting the router menu.
It`s important to know that if the router has a hardware firewall set to on, that the setting should be set to medium, as high can cause problems, in the case of windows firewall or the firewall in windows security center also running at the same time set to high so check its status in windows if enabled. Both should not be running at the same time, i recommend you disable one or the other or lower...