OK, crazy things can happen and a reboot of your modem and/or router could fix this issue.
If it doesn't then we should look at the network properties of the network card.
In Control Panel, go to Internet Options and make sure you have the following setup:
If that is good, please do a
ipconfig /all and hit enter. We would need the information from your Ethernet and/or Wireless information. If you can take a picture that would be great, if not, you can do the following command:
ipconfig /all > C:\ipconfig.txt and it will create a text file that you can copy to a thumb drive and move it to a working computer.
If this computer is wireless, and you have a hotspot, try connecting to the hotspot to see if you have the same issue.
Do you have any internet security programs like Norton, or McAfee, etc?