If you do not have a key, this method will not work. However, Microsoft offers a 90-day trial ISO for evaluation purposes through their Windows Dev Center.
But you cannot browse this directory—it requires a session cookie from a product key check. Instead, use the (find the original MediaCreationTool.exe for Win8.1 from trusted tech sites like MajorGeeks or heidoc.net). This tool downloads the exact ISO from Microsoft’s Akamai CDN. Index Of Windows 8.1 Iso
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