When I plug in the CA adapter, and press the power button, nothing happens. There are no LED lights, the fan does not turn on, no noises from the hard drive, nothing. The AC adapter appears to be good, it gets the required voltage to the motherboard. Voltage checks on the motherboard show CPU 19.5V, power button 3.34. I have tried removing hdd, ram, resetting the bios and checking the CMOS, and each time trying to power the laptop up, still no joy. I do not have the schematic diagram. How do I proceed to fix this problem?