Blinking grey folder icon with question mark on boot

Hi. Just got my system from the Apple Service center where they have reinstalled a new hard disk for me.

When I come home, and start the machine, it shows me a blinking grey folder icon with a question mark in it.

Only thing I can do in this screen is switch off the power. But when I reboot, it shows me the same icon again.

With google, I discovered that if while rebooting I press the OPTION key, then it boots me into the firmware password mode. How can I automate this? I do not want to have to always boot the laptop with Option key pressed.

Thanks for any pointers.