I have a windows 7 and i decided to finally upgrade to windows 10. I used the windows installation media as i have seen online (here, here and, several other links). I then used it, it started to download. After "Processing" to 100% it said , "your windows is not activated. Please enter your product key" and told me to insert. The problem is my windows 7 professional is ACTIVATED.
it says my windows is activated. I tried again but still the same error came. So I searched for my product key and typed it in . But IT SAID my Key was incorrect and said to insert other key. What should i do to upgrade to windows 10 except buying the windows 10 key?