Final answer:
To prevent random people from booting the OS, a technician should set a user password or set an administrator password.
Step-by-step explanation:
To prevent random people from booting the OS, a technician should set a user password or set an administrator password. Setting a password helps prevent unauthorized access to the operating system, ensuring that only authorized users can boot the system. Flashing the BIOS chip or removing the CMOS battery may interfere with the system's functionality but won't specifically prevent random people from booting the OS.