Hi,
I know you said that "I tried using the power drain method....." and that this didn't work but was it the full power refresh method?
By this I mean did you disconnect the cmos battery from the motherboard as well?
If not try the following:
* Disconnect the charger if connected.
* Disconnect the main battery from the motherboard.
* Disconnect the cmos battery from the motherboard. Here's the ifixit [guide|147070] guide that will help.
* Press and hold the power button operated for a ''full 30 seconds'' and then release it.
* Reconnect the cmos battery, reconnect the main battery, reassemble the laptop, reconnect the charger and check if it turns on.