ZBook Firefly G7 goes dead, unresponsive to power on--requires 30 seconds press of power button

[gkline]

This problem started happening a few months ago where my mouse pointer started to drift upwards once the computer has been on long enough to become warm from use. Using the mouse pointer would stop it briefly, but then it would continue. I found that if I pressed down a bit firmly on the keys surrounding the pointer, it would usually stop the drift for a minute or two. Eventually it would stop, but on a few occasions when I'd pressed firmly on the 'B' key, the computer completely shut off, and would not respond to pressing the power button. Note that when I say "firmly", it wasn't mashing the key hard. It was just a slightly more than normal pressure. I've also had on 2 occasions this happening if I grip the case firmly while moving the laptop to a different spot... and now I'm wondering if perhaps there's some kind of short vulnerability going on with internals and metal case? ZBook hasn't been dropped or mistreated.

In order to get the ZBook to restart, I have to press the power button continuously for nearly 30 seconds, with the power cable disconnected. Then it responds with the Capslock LED on, followed by a series of LED flashes on the keyboard. I understand that this clears memory completely and then the ZBook goes into a complete baseline cold boot (it's about a minute or two longer than the normal boot). But it does restart and then I can use it normally.

The problem has gotten worse now. I will leave my ZBook in sleep mode, plugged in... then come back to it the next morning to find it dead... just as I described before. No shutdowns while in use... just when sleeping. So I tried hibernating. That seemed to work, at first... but then it happened again. So then I figured it must be something to do with being plugged in overnight, so I remove the power while hibernating. The problem still happens.

NOTE that it had some prior servicing: My ZBook had a faulty keyboard (a couple of key caps separated and couldn't be pressed back onto their mounts. I sent it in to HP service and they replaced the entire palmrest, because the keyboard is molded into it. Later on, I had a memory chip fault and they replaced it, as well as put in a new battery, and installed a new case bottom as well due to the rubber stripping separating. The problem I described has started to happen about a year after that last servicing. My warranty is now expired.

I updated my firmware to the latest. This has not solved the problem.  I'm on S73 Ver. 01.22.00 - 06/27/2025. Running Windows 11, 24H2 (OS 26100.7462).

Is this some kind of known hardware issue? Anything I can manage myself or will it require HP service?