If you decide to change the Controller settings in the Bios, before you do that, set your system to boot back into Safe Mode by using msconfig.exe.  Make sure you know your PIN and Password, just in case.  Then reboot and change the controller setting and allow the system to reboot back into Safe Mode.   Once in Safe Mode, you can use msconfig.exe to set your system to boot normally and then reboot your system.  If have problems, go back into the Bios and set it back like it was.  
On installing Intel RST it says I am installing it on an unsupported platform and hence it stops the installation  Also when I launch the app Intel Optane Memory and Storage Management, it says to update your system with latest Intel RST drivers. Moreover in the Dell Support I found that this driver was available for download and marked urgent, still it won't install. Also the Intel Optane Memory... app was working before reset. What should I do?
Inspiron 5406 2-in-1, IRST driver not getting installed after reset