I boot up my laptop today, that was upgraded to Win10 from Win 8.1 months ago and was working since then, and I see a message saying "Activate Windows". I check what that's all about, considering I had it activated long ago, and I'm now given this. Error code: 0xC004C003 Error description: The activation server determined the specified product key has been blocked. So I go to the store to check its validity, but what find is that they expect me to pay $200 for my Win 10 Pro copy. What sort of prank are they pulling, allowing me to upgrade to Win 10 for free from my legit Win 8.1 copy, and then slapping me with this? I got my Win8.1 copy from my school years ago, same place I got my legit Windows copy for my desktop, and my desktop doesn't have any problems with Win10. I did have to do a system restore the other day because something screwy was happening with my WiFi, but the restore point was from a few days ago. The WiFi works now, but could that have been the cause of this? I don't know what to do.