So I just used the windows media tool thingamabob to install a fresh copy of windows home 10 pro and went through the set up without a windows key because I was going to do it later but, and much to my surprise, when it was all said and done, there was no dreaded watermark. Yet, when I went to the windows activation settings it said I did not have a key. This is my first time building so I have no idea if this is normal or not. I'm asking because I already bought a key and can't return it. Will I still need it? Anybody know anything about this?