192.168.0.1 is another IP address frequently used by router manufacturers as a default. D-Link and Netgear routers are the ones most frequently configured with 192.168.0.1 as a default address. So if you don't know your router network address 192.168.1.1 and 192.168.0.1 are good guesses which will cover 95% of the cases. If these too still don't look like correct addresses you may want to go to the home page of this website and check detailed instructions on how to get your router IP address on different operating systems and devices.
Once you get to the router administration page you will need some way to login. If you don't remember your login information you can try looking it up on the bottom of your router or a modem. It is often written there by ISP providers. Or if it is not there below are some default passwords for D-Link and Netgear routers:
Default user: admin
Default passwords: empty password
Netgear MR314, RT314 and certain other old models: 1234
All D-Link routers use username: admin
D-Link DI-514 and DI-524, DI-804, DI-604, DI-704, use empty password.
All other D-Link routers use password: admin
If you get to your router/modem administration console but still unable to login you will need to contact the person or company who performed install of the router/modem. If it is not possible you should consult with router manual on how to reset password to its factory state. Make sure to explore other possibilities before trying to reset the password since it will also reset all other settings of the router and may cause your network to work incorrectly.