"Reading between the lines", I suspect you are still trying to connect to the internet from the PC, hence a connection timeout and an inability to find a modem.
It is now the *ROUTER'S* function to connect to the ISP, you should have no ISP connection software in the PC and internet access is via the Local Area Network from the router.
Initially, you should connect to the router by ethernet cable and access its setup pages by entering its IP address (192.168.1.1?) into your web browser. Configure it with your ISP details so that it can connect automatically.