Sounds like you lost the internet connection from your ISP, modem, or cable. First try power cycling the modem, router, and PC. Try bypassing the router and connect your PC direct into the modem and see if you get internet. You may need to power cycle the modem. If it fails, work with your ISP. Also try different Ethernet cable as that can cause that issue. Check the pins in the router ports, modem port, and cables and insure there are no bent pins.