"I usually do that if the battery's not being detected."
I had the same problem with my gu502L. The laptop automatically turned on when the adapter was plugged in and went off when the adapter was unplugged. Turns out the charger was dosing out excess power to the laptop causing it to malfunction that way. The power cable connected to the asus adapter is the main culprit.it was conducting so much power that you will get shocks from the chassis when you touched it .I'm pretty sure if you change the power cable your problem will be solved. It solved it for me