Power off the Dell and Power it up holding down [F2] to get to the UEFI BIOS Setup. Then try to reset the UEFI BIOS to factory defaults. Then power down and see if your USB Flash Drive Displays. If not try to add the Boot Entry Manually: [URL]#ManualBootEntry Note I would not bother with Windows 10 Version 1909 especially on a mechanical hard drive as it has faults with the Windows Indexing for Windows Search giving dreadful performance. This has been fixed in Windows 10 Version 2004. [IMAGE]   You can download the Windows Insider Preview Slow Track ISO which will install the cumulative update KB4550936 taking you to Build 19041.207 which Microsoft have already stated is the final build of Windows 10 Version 2004. I wrote an updated guide here: [URL]
I'm helping to repair a 15 3567 that was cycling with the Dell splash screen only, and would not finish the POST. Tried numerous repair efforts that did not work. Decided to remove the hard drive, attach it to another computer and hopefully access the drive to remove some important school documents. When I got into the drive, it said that the hard drive was empty and contained no files and had a full TB of free space, which is the size of the hard drive. Totally lost and wondering what happened to the hard drive and the info on it, I reinstalled the hard drive and followed directions from Dell using their OS Recovery Tool. I followed that by downloading onto a USB flash drive, Windows 10 along with all that was on the computer when it was originally sold. The problem arises when inserting the flash drive into the 15 3567, there is no option to change the boot sequence to usb. I did have an option to run a diagnostic check on the computer and it ran for hours and reported that all the hardware had passed the tests and was operating properly. But I can't get it to boot to the USB port. The problem seems to be that  "Boot Mode is set to UEFI: Secure Boot: ON; PTT is ON". What do I do to fix this, any ideas? Please help.
How to boot to usb on Inspiron 15 3567 with UEFI