Use a USB drive to install Windows 7, 8, or 8.1.
Use a USB drive to install Windows 7, 8, or 8.1.
You're facing a common issue when installing Windows on a system with an existing installation media. The error you're seeing suggests that your computer is trying to use the original installation media but it's conflicting with the new setup. It might be necessary to remove the old installation drive and reinstall Windows from scratch, especially if you're using an 8.1 upgrade. Make sure to back up any important data before proceeding.
With just an upgrade key, a previous Windows setup must already exist for it to function (according to common knowledge)
Are you connected via a USB 2.0 or 3.0 interface? (Note that Windows 7 doesn’t support USB 3.0 natively)
connect via USB 2.0 as backup, attempt EFI/BIOS reset, then retry setup