ProBook 640 G2 keyboard flashing - won't boot up

[taherte2]

ProBook 640 G2    Windows 10 Pro (64 bit)   i7 6th gen processor   8 gb ram   128 gb SSD

When I press the power button on my ProBook 640 G2, the backlit keyboard flashes but the laptop doesn't boot up. The keyboard continually flashes on, then goes off for a short time, and repeats until I press and hold the power button. When the keyboard flashes, the wi-fi and power lights on the front come on together, go off, and then the battery light comes on and goes off. This is repeated in sync with the keyboard lights.

Battery was charged all night so it should be fully charged.

[taherte2]

The PC started working again after I switched chargers. We tested both chargers and both are outputting the same amperage so I don't think the charger was the problem. Now, five weeks later, I'm having the same problem.One thing i did notice is that the charging light on the front of the laptop does not come on when it should be charging. It was coming on during the five weeks that the laptop was working and it does flash when I press the power button.

Would love to hear what anyone thinks the problem is so I can decide on the best place to take it.