You can just try to check out these [https://www.minitool.com/data-recovery/fix-my-laptop-wont-turn-on-009.html|solutions] for a possible fixing:
# Check if the power switch wires are properly connected to the motherboard in the correct pins. They should be labeled.
# Remove the CPU and try starting up the computer. Most motherboards will give you an error. If you successfully see this error then you can assume that the CPU is causing problems.
# Some motherboards have a built in power and reset switch. If yours does, try using those instead.
# When you disconnect the 4 pins from the motherboard, if you have a dedicated graphics card then try to connect the video cable to your onboard graphics in an attempt to get something to display rather than the graphics card.