What type of screw is used here

Heya! I have doubts the screw would cause the laptop to not power on.

Does the laptop power on while it is plugged into a charger? (Such as any little led's or the screen lighting up) If that's the case it may be the battery that's bad and should be replaced.

If there are no signs of led's lighting up and it wont power even while plugged into a cable, the motherboard may no longer be working and would need to be replaced

there is a slight chance that if the laptop was opened before, the missing screw "could" be inside the casing and shorting it out.

Hope any of this helps!