Considering the variety of SMU reset instructions for different models, I usually:
1) remove power (unplug or pull battery)
2) wait 10 sec
3) press power button and hold for 10 sec
4) while power button is still held, plug AC cord back in.
5) release power button
That seems to cover them all. Many of the laptops have a set of SMC reset pads also.
Although SMU resets only help in maybe 5% of cases of no power on. But it costs nothing and is quick so may as well try.
