A UEFI system can boot only from a GPT disk, not MBR. (A BIOS system can boot only from an MBR disk and not GPT, which is why you can't take an OS disk from a BIOS system and put it in a UEFI system and expect the system to boot.) Most UEFI motherboards come with a Compatibility Support Module (CSM), which is enabled by default. It makes the motherboard actually look like a BIOS system, allowing it to boot from NTFS and MBR disk--but you lose the UEFI features and are essentially just using BIOS. If you want to run your system as UEFI, you need to disable the CSM via the motherboard's interface before you try to install Windows. Because UEFI requires a GPT disk to boot from, whatever disk you install to must have all partitions deleted from so it can be configured as GPT. It needs to show as a complete Unallocated Space. Select New on the Unallocated Space, and four partitions will be created. This means your system is UEFI, and its been configured as GPT. The Recovery partition is NTFS, and it holds the Windows recovery information. The System partition is FAT32 formatted and contains the EFI system partition that the computer will boot from. The MSR is the Microsoft Reserved Partition (which is space Microsoft might want in the future for certain disk operations such as converting from basic to dynamic). Last, there is the actual NTFS boot partition. Your UEFI system can boot only from a device that has an EFI boot loader, so after the CSM has been disabled, the only boot devices that are listed will be UEFI aware. After all of that, and Windows is installed, msinfo32 will show the BIOS mode as UEFI, not legacy.
This is what I did and it worked, but with WIN10. Not too sure about WIN7 but you will need to have secure boot disabled during the OS installation and should be turned back on after installation for WIN7.