Thank for the answer.
I try to install linux mint 20.
Although I've disabled the "secure boot" and "fast boot" options in the bios setting, it didn't work.
I guess there should be an option like "OS-Type --> Other OS" in the bios setting which enables one to install non-MS systems. (I said "guess" because it is in almost other pcs and the name of the selection may be different.)
Thanks!