I already mentioned what should be the issue and the solution.
So:
1. Press Win+R, type "ncpa.cpl", then press Enter.
2. Right click the network adapter that you're using to connect to internet, and click Properties.
3. Double click "Internet Protocol Version 4", and choose "Use the following DNS server addresses". In the "Preferred DNS server" put "8.8.8.8".
4. Click OK, and exit all the open windows. Do Win+R again, type "ipconfig /flushdns", and press Enter.
Everything should be fine afterwards.
You can read more about Google DNS, here:
https://developers.google.com/speed/public-dns