I solved my own problem. I tried downloading the Dell recovery tool again, and with this new drive everything worked as advertised. What a relief.
Hi,The M.2 memory C drive (on mother board) wore out on my Dell XPS 8930, and totally failed. I replaced it with a new 500 GB M.2 SSD, obviously the recovery tools on the PC are non-existent. So I turned to USB drive recovery methods, and have struck out on all counts. I created four USB recovery drives:1. I made a recovery USB drive at time of purchase.2. I recreated new recovery USB drive (formatted x Fat) using Dell’s Support Assist OS Recovery tool3. created a drive with only the Dell.com Win10 ISO file (formatted x Fat)4. created a drive with only the from Microsoft.com , downloaded ISO image file onto USB drive (formatted x Fat) I have used "Recover from a drive" choice for all four USB drive options mentioned above and receive "Unable to reset your PC.  The system drive cannot be found.” I used the Advanced option - System Image recover for ISO image, and used both the Microsoft and Dell ISO files on USB drives, and get a “Windows cannot find a system image on this computer” Using the "select a system image" option, I land on the "re-image your computer" screen. There I hit refresh, and the system cannot find either ISO files. Using the advance option, install a driver, both files on two separate USB drives are clearly there. I do see that this tool assumes the image is on a DVD I read at[URL] needed to install new Intel firmware so that the system would recognize the M.2 drive. I did that, and no luck. On UEFI settings, "Enable USB Boot support" is [enabled] . Obviously I'm missing something! Any help is appreciated
Clean Win 10 install using USB drives fails