I posted on here with the same laptop a while ago, and I am aware this may be a motherboard fault, but at the suggestion of someone I switched out the power adapter plug > mobo connector and tried it; it worked.
For about 36 hours.
Now when I attach the AC adapter (with the battery in) I get a single white LED flash then it goes blank.
The is no LED on the power button, pressing the power button has not affect most of the time.
Twice since then (normally if I have removed the CMOS battery, which I did when following the technical manual on how to reach the replace part) when I try to power button it will boot, and show the time error & let me change that in BIOS. Then then it restarts itself it again will not turn back on.
A further time I tried the static discharge (holding power button down for 10 seconds) trick, and it booted to windows fine, worked for 2 hours, then when I placed (gently) the laptop down on a surface it just turned itself off and went back to no power.
I have replaced the CMOS battery with a new one just in case the old was faulty and the issue persists.
Am currently trying to eliminate a faulty part while working back to the motherboard.
What I want to ask is; Is this still consistent with a motherboard fault? Am just wanting to check due to it powering up on occasion, lasting for a few hours and then losing power & reverting to its previous issue.