No laptop to date has DEMANDED I put in the HDD, ODD or SSD to turn and stay on. You can remove those for testing.
I have an IBM ThinkPad where I replaced the Mobo, Ram, and CPU and it doesn't turn on. It turns on and then promptly turns off. Lights flash and fan spins then it stops. Could this possibly be the HDD? I don't know what else could cause this.