Hello. I just replaced the motherboard in this laptop as well as the GPU. Now, whenever I simply plug in the A/C adapter, the power light comes on and it powers on for 2 to 3 seconds and then shuts down for about the same amount of time. Then it repeats this over and over again. It does not matter if the battery is installed or not, it will do the exact same thing. I do not have to touch the power button. However, if I DO push down and hold the power button, it will stop doing this. Yet when I release the power button, it continues its ON again, OFF again routine. Could it possibly be the power button causing this maddening power loop? How can I test this with a multimeter? Thank you.