Question Laptop keeps shutting down randomly

Sep 23, 2020
Hi, I am a software guy with minimal hardware knowledge. As the titles stated, my laptop is experiencing (seemingly) random shutdowns, any advice is welcome.

The problem:
My laptop (specs below) is about 4.5 years old and has been shutting down at random moments the last months. It shuts down instantly, as if someone pulls out the battery. The problem has gotten worse over time, it used to occur about once every week, but now it happens in only minutes or hours.

My laptop is a dual-boot system (Ubuntu and Windows), the problem occurs in both OSs. This makes me think that it has to be a hardware problem. (is this correct?)

Problem hypothesis:
My current hypothesis is that there is some sort of power problem, or something with the motherboard. I came up with this hypothesis because in the last week 3 components of my computer suddenly broke:
  • 1 USB port
  • The speakers
  • The fan
The fan broke down first, which I didn't think much of since it was dust-cluttered (I know, bad maintenance) and 4.5 years old. However, getting followed by the breakdown of a USB port and my laptop speakers got me thinking. Now I am highly suspecting that the components breaking down is related with the random shut downs. I think that the chances of all these three components suddenly breaking in one week are close to zero.

The fan has been has been replaced with a new fan. While replacing the fan I completely cleaned the laptop, meaning that the problem is unlikely to be dust related.

What I tried so far:
I tried narrowing down the problem by doing the following:
  • Using a different charger (I mean an identical charger but a different physical object)
  • Running without battery (powered from charger directly)
  • Running on battery only
  • Running in Windows safe mode
  • Checked for driver updates
  • Checked all connectors to motherboard
  • Took out and reinstalled RAM, leaving 1 8GB card out for now
I checked the CPU temperature using Speccy (Windows) and lm-sensors (Ubuntu). The idle temperature of the CPU was varying around 35 to 55 degrees.
Also I did a CPU stress-test. The CPU temperature during the test hovered between 75 and 80 degrees, with a max of 82. I don't think that it can be an overheating problem, since my laptop isn't reaching crazy-high temperatures and also the problem can occur within minutes of booting up (no time to heat up).

It's a stock laptop, I only doubled the memory and changed the hard drive from a HDD to SSD. Not overclocked.

Model: HP Notebook - 15-ac142nd (ENERGY STAR)
CPU: Intel® Core™ i7-4510U with Intel HD Graphics 4400 (2 GHz, 4 MB cache, 2 cores)
Memory: 16 GB DDR3L SDRAM (2 x 8 GB)
Video graphics: Intel HD Graphics 4400
Hard drive: 1TB SSD

In conclusion
I have tried every possible solution I could find online, I have no clue what else to try anymore.

If someone has any idea what it could be, or something else I can try, please let me know.

(I'm new to this forum. If I made any mistake posting this here or information is missing, please let me know)