Why does my laptop keep turning off and heating up randomly?

Hello,

I’m posting on behalf of my friend’s laptop. These are the problems that he’s noticed:

• Starts heating up a lot so the fan speeds up to compensate and is therefore loud. At this point the trackpad usually becomes slow and jittery. The laptop turns off soon after. The laptop activity when this happens is very mild e.g. watching YouTube videos or browsing the web.
• The laptop only turns on when holding SHIFT down along with the power button.
• The laptop screen glitches when typing or moving the mouse
• Sometimes, the laptop won’t turn on at all. It will get to the grey loading screen and then it will turn off.
• The laptop sporadically turns off, even if the laptop hasn’t heated up.

I think it’s important to say that we upgraded the laptop’s hard drive a few months ago (March or April) because we wanted to make the laptop faster and more catered towards creative apps e.g. Logic Pro. We upgraded it from 500gb hard drive (original Apple stock) to 1 TB SSD (Samsung EVO 860 1tb). It was working fine and actually really improved the laptop’s speed. However, could this be why the laptop is acting up?

I’m aware that this problem can be caused by a faulty or old battery however, we’ve also tested the battery using the Battery Health 2 app. It’s 5.8 years old however it’s saying the battery is still in good health. Picture attached below for reference.

Do you have any suggestions on what he could do e.g. SMC reset? He said that he did this already but that it hasn’t worked. We will try again later and update you.

We’ve tried the Apple Hardware Test too but it doesn’t take us to the normal screen, it takes us to internet recovery which then says that there are no problems.

He won’t mind replacing any parts as long as it isn’t too difficult to do or to obtain.

Thank you very much!