I bought a laptop earlier this year with Windows 8 on it. A few months ago I downloaded the 8.1 preview from the Microsoft website. Now, despite all of their "directions" on the site, I cannot go from the preview to the final version. It seems like I should be able to do this from the Microsoft Store but this will not open for me. I tried a different route but it asks for a product key. I don't remember if I have received one, or where to find it if I indeed have one. Any help would be much appreciated.