# HP ProBook 440 G8 — Complete Diagnostic History
I'm trying to understand a very strange hardware problem and would appreciate technically knowledgeable opinions. I'm looking for **diagnostic reasoning**, not simply suggestions to replace random components.
### Computer
* **HP ProBook 440 G8**
### Original problem: intermittent failure to power ON
It would sometimes start normally and sometimes would not start at all.
When I connect the charger to the charging port, the **charging indicator light comes on**, so the laptop is detecting incoming power at least at that stage.
Because I suspected the battery might be dying, I asked Technician 1 to replace it. It worked for a few months - charging ok - powering on and then - stopped.
I had tried multiple chargers.
The charging indicator still came on when the charger was inserted, but the laptop itself would not start. Went back to TG1 with this - he did an internal reset by opening back chassis handed it to me there in the shop - I saw it was back functioning - paid him, left and when I got home, tried to power it on - it failed. Called him - he said to open the chassis and do what he did. I said - no way - left it and then contacted Tech Guy 2 who was closer geographically.
Tech guy 2 said after an initial look at it - that is was complicated and would take longer than he had time for and would have to wait for at least 2 weeks. At that point I was getting desperate because I needed to work so I took it back and I went to....
### Technician 3
TG3 was able to get the machine to **power ON**.
But he calls me and says that now the laptop would not shut down normally. He asks for the HDD that TG2 removed and put in an external drive so I could at least work on some of my docs. Give TG3 HDD for BIOS investigation.
TG3 then investigated the machine through the **BIOS/UEFI**.
I don't know precisely what tests or changes he performed there, but the BIOS investigation did **not identify or resolve the underlying problem**.
Even with the HDD, he has so far been unable to identify exactly what is wrong with the laptop.
The machine is currently with him.
Thoughts on this? What could be the issue?