💬 Laptop overheats and shuts down, vents already cleaned

My laptop has started shutting down on its own, mostly when it's charging and I'm using it hard. It began about 2 weeks ago, only during long gaming sessions at night. Now it even dies during video calls once it has been running for a few hours straight. The laptop is 3 years old and I've never opened it or had it serviced since I bought it. I already cleaned the outside vents with a brush. That didn't change anything at all. The fan has also got louder than it used to be, like it's working overtime just to keep up. Maybe there's more dust deeper inside than I could reach. Or the fan bearing is wearing out. Or the thermal paste has dried out, which would make sense for a 3 year old machine like this. I haven't run any temperature software yet. I'm planning to install something tonight and check the numbers. My budget is tight, so I'd like to try the repaste myself if it's not too risky for a beginner. There are videos online for it, but I've never opened a laptop beyond the back panel. I don't want to snap a ribbon cable and turn a 500 rupee problem into a 5,000 rupee one. If anyone has done a repaste on their own, how long did it take you? Was it worth doing it yourself, or should I just pay the repair shop and be done with it? Also, does using it on the bed make a big difference? I do that more than I should. I'm going to check the temperatures first, so tell me what numbers are too high.

Repasted my own laptop last year following a video guide, took about an hour including cleanup and it dropped idle temps by almost fifteen degrees.

This sounds like it could be a thermal paste or dust buildup issue. Try running a monitoring tool like HWMonitor to check your CPU/GPU temps under load, if they are crossing 90°C+, it is worth getting the thermal paste reapplied. Also double check that all the fans are spinning; a silently failing fan causes exactly this kind of random shutdown. Worth also checking if the laptop is sitting on a soft surface like a bed or couch while in use, that alone can trap heat significantly compared to a hard, flat surface with proper airflow underneath.

It could be thermal paste, but I’d check a few other things first. Monitor CPU/GPU temperatures under load, make sure the fans are spinning properly, and check whether the CPU is hitting unusually high usage. If temps are consistently very high even after cleaning, repasting and checking the cooling system would be reasonable. If it’s shutting down suddenly, I’d avoid pushing it hard until you figure out the cause.