Hp Elitebook 850 G3 Not turning on

[Kbekaert]

Hello,

My elitebook 850 g3 won't start. I spend days searching on forums, google, youtube, hp but can't find any working solution yet. I tried the hard reset and many other button combinations. 

So here's the problem:
1. I press the power on button and it flashes white every 7-8 seconds for 3-4 sec. At the same time at the top right the wifi led blinks orange and the mute led blinks white. I cant hear any sounds of the laptop starting and it keeps blinking every 7-8 seconds.

2. I also got 4 led's at the bottom left of the elitebook that flashes together with number 1 within the same 7-8 seconds time, from left to right its a wifi led, power led, charge led and a disk led. Firstly the charge led blinks very fast from white to orange to white to orange ( 2 seconds) and after that very fast the wifi led blinks orange together with a white power led and a orange disk led (1 second). This keeps repeating together with the led's at number 1 so for 3-4 seconds There 's no led down left blinking until the power led at the top left blinks again from the 7-8 seconds interval.

3. While charging with the AC plugged in it seems that the charge led at the bottom left sometimes stays orange for around 20 minutes and then it falls out and sometimes there's no led at all. After a hard reset the same led stays white for 10 seconds with the AC plugged in and falls out after that.

Note that no shift-lock or num-lock led's are blinking during  the 7-8 se c sequence 
Anyone knows what all this means? I'm so grateful for any help around this case s. feel free to ask any more information if something in my description is not clear enough or missing.

Kind regards and many thanks!