So I upgraded my Samsung 700T to 8.1 pro via the "add features" routine in windows update. was fairly quick and painless. However, I still wanted to do a clean install. So, I downloaded the 8.1 pro ISO from Microsoft and made a boot USB from it. Plugged the usb into the tablet and restarted. The installation screen came up and I started to install, so far so good. Then it got the point where I entered my product code. I entered the new code I got from Microsoft when I did the pro upgrade and got the following message: this product key can only be used to add features to windows it cant be used to install windows. WTF! what kinda BS is this? I PAID for windows, I should be able to install it however I wish. What do they expect me to do, go buy a new OEM disk for $140 and what I paid already is just down the toilet? Kinda makes me want to put windows 7 on it. BS! are there any hacks I can do to do a clean install with my lowly "upgrade key"?