Elitebook 8570w Won't power up - 8 flashes on the power indicator

I picked up an "non-working" Elitebook 8570w off of Ebay fairly cheap.

When I got it, there was zero response from the laptop when plugged in and the power button was pressed, so I swapped out the DC input jack, reassembled the computer and now when the power button is pressed the power indicator light comes on and flashes green eight times and then shuts off. Which is better than before but obviously still not "fixed".

This is with the 150w power adapter plugged in, CPU , GPU and one stick of RAM in place and no battery.

(it didn't come with a battery and I was waiting to see if I could get it running before ordering one).

I have tried pulling the CMOS battery but it still just gives me the eight flashes even after the hard reset.

Any ideas as to what is wrong now?

 

Is your adaptor official? HP laptops can be picky on third party adaptors.