1) Remove the cell battery, then press the power button to discharge the power. After that put the battery back and connect the power core. boot the laptop.
If it can boot, done.
If the laptop can not boot, you will need to remove the battery, and the RAM, or even the boot device.
You can try to boot the laptop without the boot device to see it works or not, keep in mind the laptop will not boot into the window, but it will show you the "no boot device" error, that means the OS or the HDD may have problem.
Or try to boot the laptop without the RAM too, you will get no RAM error, that means the RAM may have problem.
Or if the laptop does not boot at all, when you remove the RAM or boot device, or both of them, that means the laptop ( MB) may have problem.