Secure Boot

Secure Boot is a new feature found in Windows 8 and later that prevents unsigned operating systems (such as some GNU/Linux distros) from booting. All computers that have Secure Boot as a feature all use UEFI. UEFI is a new pre-boot firmware that replaces the traditional standard BIOS firmware, and is basically on every new computer from 2012-present.

UEFI is backwards compatible with the old traditional BIOS firmware also, in which it's called Legacy Boot. On some motherboards, You can set your computer to boot as a Legacy computer if you have a UEFI BIOS, to boot to operating systems such as Windows XP.

I wanna disable it!

To disable Secure Boot on a Desktop computer, do the following.

1. Restart your computer.
2. Press your BIOS key when the screen shows up on boot (this is called your POST screen)
3. You're in the UEFI now!
4. You need to find Secure Boot. It should be in either a Boot tab, Authentication tab, or a Security tab.
5. After disabling, press F10/whatever to save changes and exit.
6. Congrats! Secure Boot is now disabled.

To disable Secure Boot on a Laptop, it is a bit more complicated. You can also search your laptop's BIOS key, and hold it to get to the BIOS (e.g ASUS laptops, hold F2 while starting up).

1. From the start menu, or the lock screen, open the power menu (with the power icon) and hover over Restart.
2. Hold down Shift on your keyboard, and then press Restart.
3. Let go of Shift when it says "Please wait".
4. You're now in the Advanced Options Menu!
5. Select "Troubleshoot".
6. Select "Advanced options".
7. Select "UEFI Firmware Settings".
8. Select "Restart".
9. Congrats! You're in the UEFI! Now, find Secure Boot.
10. It should be in either a Boot tab, Authentication tab, or Security tab.
11. Disable it.
12. Press F10/whatever to save changes and exit.
13. Congrats! Secure Boot is now disabled.