The Problem - System crashes once in a while to black screen and no boot disk message.

Things that I've tried:

Updated to latest 1.32 .x BOIS

Updated all drivers via Dell Support Assistant software.

Changed from SATA RAID to AHCI controllers.

TRIED TO UPDATE TOSHIBA FIRMWARE FOR TOSHIBA KSG60ZSE256G SSD's, as I suspect that old firmware could be causing the problem, by downloading the N91D4 SG6-ABDA4105-64bit.exe from the Dell drivers page for my service tag. Right clicked this file and ran as Administrator. Get error "Unable to prepare system for native mode update". My existing firmware is ABDA4101 and ABDA4102 ( 2 disks).

I think that the firmware patch cannot get exclusive use of the disks to perform the upgrade.

Made a bootable USB of Hiren's Boot Windows Pre-installation Environment, booted from that, ran the firmware update and got the same error.

Made a bootable FreeDOS USB and tried running the SG6-ABDA4105-64bit.exe but program won't run under DOS.

Extracted the .exe file using 7-Zip with a view to doing a manual update from lubuntu but whilst there is a ABDA4105.sig file there is no .bin file in the archive so don't know how to proceed further.

Any thoughts on this please?