I think that's your problem right there. Did you try the public Insider key by any chance?

Question, so did you install it using a USB key and boot straight to the stick? If you did that, you should have been prompted to enter a key. Did you enter the Insider key there? Or did you skip...

I just want to chime in.. I almost gave up thinking I lost my genuine copy of Windows. I got the update message this morning, installed Windows 10 but opted to clear everything. It went about doing...