Windows 8.1 Iso [work] Link

: If you are installing a trial or don't have your key ready, you can often bypass the initial prompt by using a generic installation key, then activating with your genuine key later in settings. Clean Install vs. Upgrade

Historically, users with a Windows 8 retail key could bypass the Windows Store upgrade by using the Windows 8.1 setup files to trigger a direct download. System Requirements windows 8.1 iso