When Microsoft released Windows 7 in 2009, USB 3.0 was not yet a standard. As a result, the installation media for Windows 7 only includes drivers for USB 1.1 and USB 2.0.
Most modern USB creation tools (Rufus, Windows USB/DVD Tool) simply copy the install.wim file to a USB drive. They do not inject drivers into the boot environment (boot.wim). When Windows 7 Setup loads, it uses the boot.wim kernel. If that kernel lacks a driver for your USB controller, it cannot see the installation source or your input devices. windows 7 usb 3.0 creator utility intel download center
Ensure your flash drive is not write-protected. When Microsoft released Windows 7 in 2009, USB 3