Question about clean installation of Windows 8.1

[sportsfan]

Hi all, Ive followed the instructions given to me by Dell Tech support and gone to the link listed under my Service Tag where there is the option to download my Windows 8.1 ISO image along with instructions which Ive printed off.
I will be installing from a USB flash drive and the instructions to create the bootable USB installation media are straight forward and easy to follow using Diskpart. Then simply Mount the image and copy all files over onto the USB flash drive.

Im a little confused though when reading the instructions under How to Reinstall Windows 8.1. there are two options PCs with BIOS boot mode and PCs with UEFI boot mode. I purchased my Inspiron laptop late 2015 so it has UEFI boot mode with Secure Boot. Under the UEFI boot instructions it talks about disabling Secure Boot for USB installation media and set Boot order to Internal ODD device. I don't understand..a USB flash drive isnt an Internal ODD device as far as im aware.
So without doing anything to System Setup Ive tried inserting a USB flash drive and tapping F12. It says UEFI boot mode and Secure Boot is enabled and the flash drive is listed second one down underneath my Toshiba hard disc. It seems to me that I have to follow the instructions for PCs with BIOS boot mode even though my system is UEFI boot mode!! Am I missing something here?

 

[RolandJS]

I thought UEFI's Secure Boot and Fast Boot can be disabled. And, with the usb stick in the slot you're going to boot it from, you should be able to pick usb device from within the UEFI menu. I don't think you can make the laptop a BIOS laptop. Others should be coming into this thread real soon.

 

[sportsfan]

My point is I haven't gone into the F2 system settings at all to Disable Secure Boot. I just restarted my PC tapped F12 and the menu comes up as UEFI boot Mode with Secure Boot Enabled with my hard drive listed first and directly underneath it my USB flash drive is listed for selection. Does that mean that it isn't necessary to Disable Secure Boot on all systems because on mine I haven't disabled it.
Can I just select the USB flash drive in the list with Secure Boot Enabled and continue with the Windows 8.1 clean installation or am I likely to have problems because the Secure Boot is enabled?