Specs: HP Pavilion dv6 running Ubuntu 18.04

Description: It's a SECONDHAND computer. The bottom left corner area by the track-pad starts getting hot while in use; it eventually shuts down, esp. during heavy use. This can take some time, max. ~ 45-min.

Additional info: computer makes some noise at times. I think it's the fan or the HDD. Incidentally, the WiFi adapter is not working, but it's equipped ---I have checked.

> I don't know where to start fixing. I thought of running some diagnostics on the hardware, but I don't know what to look for, e.g. temperature, etc. Please advise. flip it over and take off the back plate - can be tricky with multiple screws - or some just push and slide off, all vary slightly.

with complete access to in innards, you need to remove any dust build up; compressed air, brush, whatever works for you.

if still no luck, sitting them on those ELEVATED USB powered fan platforms may be the solution.Find the solution below:

1. Using coolin pad is a solution of overheating.
2. kindly check in task manager which process is using much resource and close it.The use of a cooling pad under the laptop would be a temporary solution, essentially a band-aid.

More than likely the fan vents are plugged up with lint and such.  The extra noise you hear may be the fan as its speed is ramped up to try and compensate for the overheating.  It's also possible that the fan is failing and you are hearing the friction of the bearing surfaces wearing away.  You may need to disassemble the laptop and thoroughly clean the fan vents and shroud that may be preventing good airflow to the cpu heatsink.  You can find disassembling instructions/videos for just about any make of laptop by using your favorite SEARCH engine.

Since the laptop has been shutting down due to overheating, it may mean that you also need to replace the HEAT transfer grease between the cpu and the heatsink.  Under normal conditions the grease doesn't dry out but during overheating conditions it's very commmon for the grease to dry out and become TOTALLY ineffective.