ProBook 640 G2, the backlit keyboard flashes but the laptop doesn't boot up

[Rusell]

ProBook 640 G2    Windows 10 Pro (64 bit)   i5 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.

[Jupitero]

Hi,

When you power on the laptop, the Caps Lock should blink in a specific pattern to indicate the source of problem. The blink codes are described in this HP Video: https://www.youtube.com/watch?v=5MNl-_uNOWM

Report back here with the error code and let's see if it can be repaired.