What issue does my laptop have? PSU / CPU / Motherboard

[sosavip]

So just last night my laptop started going through a series of shutdowns, where I'd be in the middle of something and it would turn off on its own, no warning beforehand. I got in touch with support for the manufacturer and they're telling me that the worst case scenario is the motherboard being dead. After some testing, letting the laptop turn on, it would keep shutting down without warning, but usually on a routine, every 20 mins. After its final shutdown, it would no longer turn back on, only the light would flash where the power is and then nothing. I could press the power button another time and it does the same thing. The LED indicator showing my battery life lights green, but the indicator for the adapter lights orange. The laptop will not turn on off of battery life alone, nor with the adapter alone. I did some searching and found a few threads, one pointed out that if there's a flash at all it might not even be the motherboard, it could either be the adapter or the CPU. I'm really just trying to narrow down to the final issue. I'm hoping it leans more towards the PSU entirely, with the adapter and the battery, instead of the motherboard or the CPU. Any info and tips would be greatly appreciated, thanks.

 

[Robert Ban]

I would replace thermal paste of cpu/gpu onto laptop, if you are quite unsure how to do that or youre unsecure about that take it to reputable repair shop and explain them.

Before doing anything:
Is it under warranty?
How old is it?
Model and brand?(Acer, Dell, etc.)

 

[sosavip]

I would replace thermal paste of cpu/gpu onto laptop, if you are quite unsure how to do that or youre unsecure about that take it to reputable repair shop and explain them.

Before doing anything:
Is it under warranty?
How old is it?
Model and brand?(Acer, Dell, etc.)

I'm not sure of the brand to be honest, it's an Origin PC laptop, no longer under warranty and it's only a year and a half old. What exactly would replacing the thermal paste do?

 

[Robert Ban]

Probably if the laptop sat into shop the thermal paste dries and results maybe what youre experiencing.
Cpu overheats and shuts off or gpu. Worth trying before swapping adapter, worst case scenario motherboard started to fail.

By sat into shop i meant sitting in shop until its sold 1 year+ 1 ans half of your usage. Usually thermal paste limit is 5 at max before starts tk be stone.

Sorry for typos, phone is giving me hard time....