If you’re wondering how to start a laptop without power button then here are some methods that you can try if the power button of your laptop is damaged or broken:-
1. Using keyboard- You can turn any key of your keyboard to a power button by netering the BIOS of your laptop and from the ACPI management you can select any key of your preference as power button.
2. Motherboard- This method is hardware-based, so for that you have to open the base of your laptop and then remove the connections between the power key and the motherboard.