On UEFI systems, when you try to install Windows 7/8.x/10 to a normal MBR partition, the Windows installer will not let you install to the selected disk.
Windows cannot be installed to Disk # Partition #. (Show details)
This message is displayed if you show the details:
Windows cannot be installed to this disk. The selected disk has an MBR
partition table. On EFI systems, Windows can only be installed to GPT disks.
Additionally, attempting to install to an unpartitioned MBR disk will not result in the desired configuration since the disk will be converted to GPT.
The Windows installation media is being booted in UEFI mode.
Boot the Windows installation media in non-UEFI (Legacy) mode. If the BIOS boot selection menu shows both UEFI and non-UEFI boot modes for the booting drive (CD/DVD, USB flash drive) choose to boot the non-UEFI item. Otherwise, enable Legacy booting in the BIOS. Depending on the BIOS this may require disabling UEFI booting.