Heat is the silent killer of laptops. It rarely breaks anything overnight, but a machine that runs hot for months will wear out its battery, throttle its own speed, and eventually damage the motherboard. The good news: most overheating has boring, fixable causes.

Dust is the number one culprit

Laptops pull cool air through small vents, and with it comes dust, lint and pet hair. After a year or two, the cooling fins can be blocked by a felt-like layer that traps heat inside. A professional clean restores airflow and often drops temperatures by 10 to 20 degrees.

Thermal paste dries out

Between your processor and its heatsink sits a thin layer of thermal paste that transfers heat. It dries and cracks with age, and once it does, the heat stays in the chip instead of reaching the fan. Repasting is a routine part of a proper cooling service on any laptop older than three years.

Soft surfaces block the vents

Using a laptop on a bed, couch or pillow smothers the intake vents underneath it. If your laptop lives on soft furnishings, a flat tray or stand is the cheapest cooling upgrade there is.

Constant full-speed fans can mean software, not hardware

If the fans roar even when the laptop is idle on a desk, check what the processor is doing. Runaway apps, stuck update processes and malware all keep the CPU pinned and the fans spinning. In those cases the cooling system is doing its job; the software load is the problem.

Warning signs it has gone too far

Sudden shutdowns under load, a machine that slows to a crawl after 20 minutes of use, or heat you can feel through the keyboard are all signs of thermal throttling or worse. At that point, keep using it as little as possible and bring it in. A free diagnostic will show whether a clean, a repaste, or a deeper repair is needed, and most cooling services are completed the same day.