Laptop is,not turning even the power light is not on

Before diving too deep the first things I usually check for in No Power situations are bad charger and bad battery. Either of these could cause the light to not come up. I have also seen RAM that has come slightly loose cause this issue. Test and see if the machine will come on without the battery connected, or after you have reseated the RAM.

Of course it could also be none of these, but it’s a start.

Can you confirm the model of your laptop just to be sure we send you to the correct place? If it is in fact a ProBook 450 G6, the service manual from HP is available at their website.