Notebook Boot and Lockup

Recently the battery status icon in the notification area of my notebook's screen began to display the "plugged in, battery not charging" text that has plagued so many others.

I recently fixed this problem on my sister's cheaper HP notebook by uninstalling the battery's driver, removing its battery after shutting down, and then restarting the computer. The battery in my Spectre X360 notebook is not removable like hers, but I finally succeeded in temporarily solving my own problem with a hard reset instead (effected by depressing the power button for 15 seconds, and then restarting).

When the plugged-in-but-not-charging problem soon re-appeared, however, I tried the same fix a second time, but  found that now my Spectre X360 will not restart at all; depressing the power button only causes the battery light to blink 3 times.

I know that the AC adapter is functional. By plugging it into the notebook I can cause the orange "battery-charging" LED to display, although I don't believe that it is actually now charging the battery, because the LED never changes to a steady white glow no matter how long I leave the AC cable plugged in. Recently when the notebook was booted I ran a battery check in the HP Support Assistant, and it reported that the battery itself is functional, too.

I have read other reports that the blinking-battery-light problem is caused by a faulty motherboard, which HP is charging $500+ to replace-- despite the evident prevalence of the problem-- on an out-of-warranty notebook. I am already running my Spectre X360 on an HP replacement motherboard, because only two months after I'd purchased the notebook in April 2015 it abruptly switched itself off to black, and afterwards played completely dead.

After HP returned my Spectre X360 from warranty service in June 2015 I eventually discovered two shortcomings of the replacement hardware that it had installed:

1) the replacement motherboard lacks the hardware sensors necessary to disable  keyboard input and enable automatic screen orientation when I try to use the X360 in tablet mode, rendering this expensive feature of the computer completely unusable; and

2) the notebook will not power on when the AC cable is plugged in, but will only boot on battery power.

This latter defect precludes use of any troubleshooting measure that disables the battery after shutdown.

My Spectre X360 is full of expensive licensed software and personal work that, although backed up, would be difficult to transfer to a new machine, so if HP insists upon charging me $500+ to fix for the problem that I just I've described I imagine that I will knuckle under and pay. But this third motherboard must finally fix all of the power-supply issues once and for all, and allow me to make use of the tablet-mode capability that this model so prominently advertises.