You can try an NVRAM reset. Disconnect the charger and battery (if accessible), then hold the power button for 5 seconds. Release the button, reconnect charger, and try powering the system on.
A BIOS/EC reset is worth a shot, too, if you know how to get to the CMOS battery and remove it. Worst case is hardware failure - 6 months in, though, so you should be under warranty.