Hi,
If you did forget your router's IP Address, no worries, just follow these steps to find out what it is
1. Press and hold the Windows Key (near the left ALT on the keyboard) then press on R
2. On the box that opens type CMD
3. On the window that opens type ipconfig
4. Browse through the results, the numbers that follow DEFAULT GATEWAY under Ethernet Adapter Local Area Network (browse up the window) is your router's IP Address.
5. Type that IP Address on your web browser's address bar and gain access to your router (make sure you're connected to it via cable)
Hope this helps