I have Windows 8.1 Single Language 64 bit. I downloaded the Windows 10 upgrade twice and both times it failed to upgrade. . In the first instance I was faced with Windows Update error 80240020. I had no option but to download it again and so I did. This time immediately after the download finished Windows Update showed error 80240FFF. The Windows BT folder is at 140 MB. The downloaded file didn't extract to the Windows BT folder. But in the Software Distribution Folder I have found the ESD file of about 2.7 GB. Can I use it in any way to upgrade?
Also can I upgrade using any other way like by downloading the ISO file? How can I obtain my free Windows 10 key in that case?