Hello,
Thank you for posting in Microsoft Community forum.
Based on the description, I understand your question is related to boot.
The message "Reboot and select proper boot device or insert boot media in selected boot device and press a key" indicates that your computer's BIOS is unable to find the bootable drive with your operating system.
Check your hard drive or SSD is properly connected to your motherboard. Loose or disconnected cables can prevent your computer from locating the boot drive. Enter your BIOS/UEFI settings and check the boot order. Make sure that your hard drive is listed as the first boot device. If you have another computer available, try connecting your hard drive to it and see if it's recognized.
Also, you can try boot from a Windows Installation Media:
Create installation media for Windows.
Insert the Windows installation USB or DVD into your computer.
Restart your PC and boot from the installation media.
Choose the "Repair your computer" option and then navigate to Troubleshoot > Advanced options.
From there, you can try options like "Startup Repair" or "System Restore" to fix potential issues
Have a nice day.
Best Regards,
Molly