I would then load wireshark on the pc and attempt to capture the data coming to the pc. This will show you if the data is making it through the router and it is the pc not responding. This is to show where a configuration is not correct. It has to be the router or the pc but you have tried all the common things on both.
You want to run as little traffic as you can on the pc. Try to use a different device to request one of the port scanning sites. This is to avoid having to capture all the web traffic going to that site. It is possible to filter by port but wireshark is kinda hard for new people so it is best to just capture and manually look through the data.