You can try to restore the factory settings, press the reset button using a sharp object such as the tip of the pen or the needle or paper clip, press and hold for 20 seconds, release and wait until the router reboots.
Open your favorite web-browser and type the default IP address of the router, according to the router brand you are using. Some of home Router is 192.168.1.1
Brand Model Protocol Username Password
D-LINK ADSL HTTP admin admin