The way I did it with the tool. 1. Download and save the iso 2. Open the Windows 7 DVD Tool and put it on a flash drive.You may want to disable your antivirus software, while downloading the iso file. Also, if you have a Windows 8 key and try to install 8.1 with the 8 key, it won't work. You need to use a generic Windows 8.1 key, which you can find online. Then after 8.1 is installed, right-click This PC>Properties>Change Product Key or you do the same through the Charms Bar's Settings window and enter the Windows 8 key and activate it.