Secure Boot is a feature designed to prevent malicious software and unauthorized media from loading during the boot process. This option is enabled by default, but can be turned off in UEFI / BIOS.
Bootable media from previous versions of Windows may not be recognized by your Windows 8 desktop. You can change the Secure Boot setting and it should recognize the bootable device.
- Press and hold the power button for 10 seconds to completely shutoff your computer.
- Power on the system. As soon as the first logo screen appears, immediately press Delete to enter UEFI / BIOS.
- Use the right arrow key to select Authentication.
- With Secure Boot highlighted, press Enter and then the down arrow to select Disabled.
- Use the right arrow key to select Boot Options.
- With Launch CSM highlighted, press Enter and use the down arrow to select Always.
- Press Enter.
- Some models have a Boot Filter option in the menu. If this option is present, change it to Legacy.
- Press the F10 key to save changes and restart the system.