Please visit 192.168.1.1, use 'admin' for both the username and password. If this does not work check the label on the bottom of your router.
Go to Advanced > Internet Setup
The last step is to head on over to ADVANCED tab and select Advanced Setup on the left hand side. Click on VLAN/IPTV Setup and make sure that "Enable VLAN/IPTV setup" is unticked.