Genuine Windows 8 units do have a BIOS options; called "Secure Boot" and "UEFI Boot".
These options have to be changed if you want to boot from an external device like an USB stick or a bootable CD-media.
Please change the option "Secure Boot" to "disabled" and the "UEFI Boot" to "CSM Boot" in order to allow the system to boot from external devices.
If your external boot device contains a secure boot key (like Windows 8 or Windows PE 4.00), then you do not need to change anything in the BIOS setup.
Procedure to boot from an external device:
1. Power on the system and while the "TOSHIBA" logo appears, press [F2] key to enter the BIOS Setup Menu.
2. Select [Security] tab and set the “Secure Boot” to “Disabled”. (Refer to <Pic.1>)
3. Select [Advanced] tab and go to “System Configuration”. (Refer to <Pic.2>)
4. Set the “Boot Mode” to “CSM Boot”. (Refer to <Pic.3>)
5. Press [F10] key to save and exit.
6. Press [F12] key at "TOSHIBA" logo screen to toggle between the bootable devices and choose the medium which you want to boot from.
Once you are finished and you want to return back to normal operation you need to revert the Bios settings:
- Power on the system and while "TOSHIBA" logo is being shown, press [F2] key to start BIOS Setup Menu.
- Select “System Configuration” in [Advanced] tab.
- Set the “Boot Mode” to “UEFI Boot”.
- Set “Secure Boot” in [Security] tab to “Enabled”.
The installed Windows 8 OS will not boot up, if you do not revert the BIOS settings !