During the summer I got the free upgrade to windows10 from my already activated copy of win 8.1. Everything was all hunky dory until today when it said that it wasn't activated. So I tried the code that I used for the 8.1 activation and it did not work. What the heck Microsoft? Thought this was a free upgrade. Is there anyway that I can activate it without rebuying the os? And if I cant, is there a way to get rid of the stupid watermark?