What you need to do is to connect the cable from the modem to the router and then connect that router to the computer using a LAN cable.
On the computer(windows) you need to find the default gateway
Steps to find the default gateway :-
1. Open run box(windows button+ R)
2. Type cmd.
3. In black color windows type "ipconfig" without codes.hit enter button
4. You will find the default gateway over there.(eg 192.168.0.1)
Now once you find the default gateway enter this gateway in URL of your browser.
It will ask you for user name and password.
The default user name and password is written behind the router box.(eg username:- admin /password :- password)
Once you enter this info the computer accepts the internet connection.
I hope your issue is fixed.
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