Few months ago, a MS technician told me that W10 runs only with UEFI. I am bit surprised, are you really sure you can run W10 without UEFI?
Dont know, since I have *nix*. OK, my learning.

The Desktop on which I installed windows 10 is a 2009 HP machine which has no UEFI capability. It was an interesting experience as I had not installed any windows system since W2K, slow and multiple reboots required but eventually installed? Had to reinstall the Grub bootloader of course.

The few computers I have are not UEFI so I don't use it. My reading on the subject indicates that if you are using GPT partitioning, with windows you MUST use UEFI while with major Linux distributions it is not necessary. That might be what the technician was referring to.

http://www.zdnet.com/article/windows...our-pc-run-it/

https://www.microsoft.com/en-us/wind...specifications

Not needed.

If you want to use it then this is true. Some OEM's may be required to use it as part of their MS agreement.

"Secure boot requires firmware that supports UEFI v2.3.1 Errata B and has the Microsoft Windows Certification Authority in the UEFI signature database."