Can't Load Windows 10

According to Microsoft you can install Windows 10 free of charge if you have a valid Windows 8.1 license.<br> <br> I have a valid license but Windows 10 will not install. It keeps asking for a product key. I enter the Windows 8.1 product key but it refuses to accept it.<br> <br> I called Microsoft Customer care, and got through to a very sweet lady in Estonia. She listened to my story and said that I should call the Technical Support number because it should accept my Windows 8.1 product key.<br> <br> Technical support does nothing bu tell me how great Windows 10 is and that I can get it free of charge, but THEY NEVER ANSWER THEIR ****** PHONE!!!