Weird internet connection problem wif desktop

Hello,

I have an internet connection problem with my father's desktop despite the fact all the laptops of me n my siblings are working perfectly fine.

The destop is connected to the router by LAN. My usual understanding is that if any computer connected to a network(wif internet) by LAN should successfully get internet connection just by simply connecting it.

It was working fine until my father suddenly said it was not working. I am suspicious over my father toggling with any settings for fun. It initiately cause "limited connectivity" (something which i feel will onli pop out on wireless).

after some further toggling by my father, it has returned to normal network connectivity but internet connection was still not working.

I have ran out of options and will definitely not want to do anything to my router which is serving my well for my wireless needs.

Please advise me on what I can do to solve this problem. Thank you.