OK, I've been noticing this similar thread all over the internet and it seems that the issue is the "power board".
Basically the on/off switch starts to wear.
So I went to a place to have them replace it, but they didn't want to deal with a laptop so what I ended up doing
what seemed to help was to split the back part of the laptop.
OK, that means nothing, and I'm having a hard time putting this into words. Maybe I'll do a video shoot & post
to youtube later, but you know how you normally want to take the cover off of a laptop to access the motherboard?
There's a phase where they say use a guitar pick to take the cover off.
Well, I just did that near the top of the laptop (closest to the power switch), and it's opened like 1/16" of an inch
(1 or 2 mm) and leave it that way. No screws. No taking apart entire laptop. Literally takes 10-15 seconds
what I think this does is keeps the power switch lifted high enough to not touch the contact that causes the
system to shut down.
Your mileage may vary!
Funutation