Secure boot is not supported by Windows 7. UEFI boot is supported but many IT departments prefer to leave UEFI boot disabled to preserve compatibility with operating system images. As secure boot is not supported by Windows 7, this will need to be disabled.

Is Windows 7 UEFI or legacy?

You must have a Windows 7 x64 retail disk, as 64-bit is the only version of Windows which supports UEFI.

Is UEFI secure?

Despite some controversies related to its use in Windows 8, UEFI is a more useful and more secure alternative to BIOS. Through the Secure Boot function you can ensure that only approved operating systems can run on your machine. However, there are some security vulnerabilities which can still affect UEFI.