You recently inserted a new hard drive in your Windows 10 desktop computer, but when you restart it, the disk appears in the BIOS/UEFI but not in File Explorer. What will be your next step?

Because the drive presents in the BIOS/UEFI, you know the data and power cables are properly connected. The drive will not appear in File Explorer until it has been partitioned and formatted. There is no need to reinstall the operating system or replace the hard disk. Neither is defective.