Hi so we bought Microsoft surface pro 3 with windows 10 on them and Microsoft told us during the purchase that we could downgrade as windows 10 has downgrade rights to 8.1 we were told we could call them and walk us through the process. So far I've been on hold for 2 hours waiting for a tech to help get me a windows 8.1 product key. Anyone know any way to downgrade from 10 to 8.1 without reinstalling 8.1 pro the disc I have asks for a key. I tried using the windows 10 product key recovered using nirsoft prodkey software. That doesn't work. Any help greatly appreciated.