Hi There,
Another thing you can try yourself is to check if the problem is not just a loose component, you’ll need to open up some/all of the panels though.
First thing to try is to remove and re-seat the “easy to get to” components like the RAM and SSD/HDD etc.[br]
Also take out the main battery whilst testing, it should be able to start up with the AC adapter alone.
A bit more advanced but do-able check is to take the CPU off and re-seat it. but for this you’ll need to get some new thermal compound and you’ll need to remove the old compound with some q-tips and rubbing alcohol from the heatsink and CPU before assembling back together.
If it still doesn’t work then the next step is a complete disassembly and testing all components unfortunately, for this it’ll be best to take it in to a repair shop that has the proper spares / testing equipment on hand.