Laptop overheating and shutting down

Platy

I have an issue with my three-year-old laptop overheating and shutting down while playing games. After some time, the case gets very hot, the framerate drops and the computer eventually shuts down. I've found that I can prevent the shutdown if I enter a menu and wait some time for the heat to dissipate.

What is weird to me is that these shutdowns haven't been an issue until last month. I didn't change anything about the environment in which I operate the laptop and I also keep Kaspersky on it and have searched for malware multiple times. I also opened the laptop in order to check whether I would find any buildup of dust (I found barely any).

I'm going to buy a new PC this month, but I would like to continue operating this laptop and I also encounter slowdowns while using the internet which I think might be heat-related.

Does anyone have another idea what could be causing this extra buildup of heat?

Gaslight

Apart from dust buildup (which apparently isn't the issue), are you sure the fans themselves are spinning properly and not failing?

Platy

I can hear the fan spinning like it did before, the fan speed seems to be at 5500 rpm while playing games. What is weird however is that the fan will sometimes start to howl loudly a few seconds before the system shuts down, but not always.

Skeith

If the fan noise were consistent, I'd blame it on that. It's an interim solution, but maybe you could try keeping it on top of a couple of wooden dowels so it's not resting directly against the surface of your desk or whatever.

illig

if you've already opened it up, do so again and make sure there's good contact between the heatsinks and the chips that are being cooled... i saved an overheating laptop several years ago by scraping off the thick layer of heatsink goop/tape and applying a nice and thin layer of some new heatsink paste

Platy

I opened my laptop again and this time removed various components, including the fan. I found a thick mat made from dust and hair inside the fan's vent which I had been unable to see without removing it. The mat was so thick that I had to tear it away by hand.

The systems still runs hot, but less so than before. I will also replace the heatsink goop once I can go out and buy some.

Platy

So the following thing happened:

I suddenly heard the fan spinning loudly, then the system shut down. When I started it again, the screen stayed black, with the fan howling. Now the fan will only howl for a second before the power will go out with a clicking noise from inside the laptop.

Any advice?