My Asus A54l Fails To Boot

I have an Asus a54l with a k54l rev 2 motherboard. Recently it turned off by itself and failed to boot afterwards. By that I mean, when the power adapter is connected it powers on by itself, the power, caps lock and num lock lights remain on, but it shows nothing on the screen nor does it respond to keyboard inputs. I noticed the power button flex cable was a bit damaged and tried replacing it with a random flex cable I found. It still powers on by itself but now it turns off by itself after some seconds. The power button is unable to power up the laptop from the battery, probably because the battery is too low. However, the battery does not seem to charge even after plugging it in for several hours.I've tried taking out the CMOS battery for a while, I've also tried my CPU in a friend's laptop and realized its not a CPU problem. I've tried booting with the battery out, with the power button flex cable out, still same behavior: it powers on by itself then does nothing else. I've tried removing any component I can; hard drive, ram, CPU, CMOS battery, battery itself, power button flex cable; still same behavior. It seems it is a problem with a component on the motherboard. Any help with identifying the problem will be greatly appreciated.