Select USB flash drive (it should be the default choice) and insert the USB drive.After the download completes, select Install by creating media.Type in your Windows 8.1 product key and initiate the download.Download and open the Install Windows 8.1 setup file from Microsoft.You will have to follow these steps next: Please note that the default Windows partition (usually 'C') has to have at least 5 GB of free storage. But, you can use it to download the ISO file directly from Microsoft's servers. Obviously, you cannot install Windows 8.1 using just the product key. How Does the Windows 8.1 Product Key Help? Please note that you need a Windows PC for this task.

My colleague Wayne Williams has already written a guide which details all the steps that you have to go through.

If you have a Windows 8 product key, you can download the Windows 8.1 ISO file directly from Microsoft's servers, and create a bootable USB drive as well.

Windows 8.1 DVD, ISO file or product key.

To create a bootable Windows 8.1 USB drive you will need the following:

1 8 to usb