I bought a used Lenovo desktop with Windows 10 upgrade. (factory Windows 8) Windows 10 runs fine except "UEFI firmware settings" option somehow disappeared or were never in place. It refuses to boot anything other than the original HDD with Windows 10. I tried booting from USB, tried putting another computer's primary HDD, tried removing all drives. If I do a cold startup and press any of those F keys, the monitor stays blank, nothing happens. I need to enter BIOS, disable secure boot and install Win7. What are my options except trashing the mainboard? Thanks. Edit: I don't understand how this is related to advanced startup. There are no UEFI settings option in advanced startup.
There are a number of ways to enter the BIOS/Firmware configuration utility on Lenovo laptops.
Read this Lenovo guide for more information: https://support.lenovo.com/bd/en/solutions/ht500216