I re-installed Windows on my ASUS X453s laptop using usb thumb stick, but the PC won't boot into the thumb drive to initiate installation, there is simply no option to use device on Windows 10 Advanced Startup. Based on the question and the answer here, I disabled the
Secure Boot Option, and enabled
Launch CSM, restarted PC, hold the ESC key, select USB drive and installed Windows 10 without any problem.
However, after installing, I reverted the BIOS setting to default, which enabled
Secure Boot Option and disabled
Launch CSM, then after a restart, the PC boot straight into BIOS, without
Windows Boot Manager available on the boot option (it was there before re-installation). If I disabled
Secure Boot Option and enabled
Launch CSM again, PC boot into Windows just fine, and there are two option to boot in BIOS, #1 CD drive, #2 Hard disk, but there is still no
Windows Boot Manager available.
How do I rectify this?
Since before re-installation PC will boot into Windows even if Secure Boot is enabled. I think I need to add Windows Boot Manager manually, but there is no "add a new boot option", only "delete boot option" is available.
If my assumption is correct (this is my first UEFI machine!), I re-installed the new Windows as non-UEFI OS, that's why I can't boot into it with Secure Boot enabled, but I can't figure out a way to install it without disabling Secure Boot. The Windows used is