Microsoft has replaced BIOS with UEFI has a firmware validation process, called secure boot, that helps to prevent malicious software applications and "unauthorized" operating systems from loading during the system start-up process. Systems which come with Microsoft Windows 8.1/8 pre-installed typically have enabled UEFI Secure Boot, and ship the Microsoft keys in the firmware.
Sometimes, you need to disable Secure Boot on your workstation or laptop, because:
During the initial stages at boot, press the DELETE key to enter UEFI firmware settings, and go to step 4 below.
|HP Secure Boot||AsRock Secure Boot|
|Asus Secure Boot||Acer Secure Boot|