BTW: This is a feature of Win 8...that makes it more secure

What does Secure Boot do?


Essentially, it prevents malware from attacking your computer through the boot sequence.

Malware that enters through the bootloader can be very difficult to detect and stop, because it can infiltrate low-level functions of the operating system, keeping it invisible to antivirus software.

All that Secure Boot really does is it verifies that the bootloader is from a trusted source, and that it hasn’t been tampered with.

Think of it like the pop-up caps on bottles that say “do not open if lid is popped up or seal has been tampered with”.

Secure Boot is not something that Microsoft came up with.
They’re the first to widely implement it, but they didn’t invent it.

It’s part of the UEFI specification, which is basically a newer replacement for the old BIOS that you’re probably used to. UEFI is basically the software that talks between the OS and the hardware.

UEFI standards are created by a group called the “UEFI Forum“, which is made up of computing industry representatives including Microsoft, Apple, Intel, AMD, and a handful of computer manufacturers.
What does Secure Boot do?

Essentially, it prevents malware from attacking your computer through the boot sequence. Malware that enters through the bootloader can be very difficult to detect and stop, because it can infiltrate low-level functions of the operating system, keeping it invisible to antivirus software. All that Secure Boot really does is it verifies that the bootloader is from a trusted source, and that it hasn’t been tampered with. Think of it like the pop-up caps on bottles that say “do not open if lid is popped up or seal has been tampered with”.
Credits and more info:
If I Buy a Computer with Windows 8 and Secure Boot Can I Still Install Linux?