I have installed a clean Win7 machine on a network where my own PC is connected. When I navigate to google.com from my PC (Win 8.1) I receive proper valid TLS connection. Yet when I navigate to google.com from the Win7 machine I get an error which says: "This page is insecure (broken HTTPS)" and after that a warning about a SHA-1 certificate.
Why is this happening? What is the difference in the certificate of each machine?