The same problem with Firefox, Internet Explorer and Chrome, a new and updated Windows 7 installation.
Do not valid certificates for most sites.
If you have installed Avast antivirus, this is your solution.
1) Open Avast window. press "Options" at the bottom of the left column in brown color. (Be open a new window).
2) Once the "Options", choose brown column to the left of this window, the option "Enable Protection" window. (new window will open.)
3) Once in the new window select the third item "Web Shield" and make Click on "Customize". A new window opens.
4.) In the new window, uncheck the "Enable HTTPS analysis" box.
5-) Ready and try.
Greetings.
Jorge