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#11
Surojit, your computer does have the UEFI features but the present windows installation does not use it, that others already said.
After following the steps suggested by hotkey the computer is not bootable, that is also the right situation. It converted the system to a UEFI system, but the disk is still Legacy that cannot boot into the UEFI environment.
In this situation, either go for a clean install at once or load optimized defaults in BIOS to use the computer for now; follow the steps again just before you are totally ready for a clean install.
What makes me rub my chick that the USB boot is not appearing in the boot menu. Earlier I have used a 61 series board for a few days; USB boot was right there.
Fat32 is not a problem. See here: UEFI Bootable USB Flash Drive - Create in Windows
Well, after disabling CSM, set all the available options to "UEFI First". In the UEFI environment of the BIOS, you will get an option "Fast Boot". Enable it. After enabling Fast Boot, you will be able to access "USB Support". Set it to "Full Initial". Hopefully then it will boot from USB.
I am uploading the full manual of the motherboard/BIOS Setup in my OneDrive. Please read pages 23 and 24 for more details: Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.
Yes, I am from West Bengal. :)