Laptop doesn't work anymore? - 2

I flashed my laptop bios chip via usb flasher because of a failed bios update. Before I put it back together, I turned it on to make sure it worked. He went on and started booting. (Before that it did not turn on, only the fan had turned, the leds lit but no reaction from the display)

I switched it off again using the power button and finished assembling it, but after that it didn't turn on. (no reaction at all, only the charging LED lights up when the power supply is plugged in)

I've tried everything. Hold down the power button, press it several times, completely disconnect from the power and press the power button, checked for short circuits, just what you know.

And none of it worked.

I really don't know what to do next, I can't just throw it in the corner and forget it. I would like to find out what exactly is going on and how I can fix it, but how?

You must have pulled something out when assembling it, because before it was still running. So open up again and take a look, otherwise you have no choice.

HI. I've disassembled it several times. However, there's nothing that is not closed.