What Causes Overheating In Laptops?
When a laptop gets too hot, the cause almost always boils down to one of three main issues: Dust and dirt blocking airflow through the unit; a dead fan; or environmental causes.

Whatever the cause, the unit can't get rid of its heat, and temperatures climb inside the case. If you're lucky, the laptop's heat-sensing circuits will shut everything down when temperatures reach dangerous levels; you may lose data, but your hardware will probably survive, at least for a while.

If you're less lucky, you'll start getting data errors or lockups. Here, too, you may lose data, but you may be able to save the hardware through a prompt manual shutdown.

In a worst case, or after repeated lesser overheating episodes, your laptop may simply end up cooked to death; either inoperative, or so unreliable as to be worthless.

Of the three main reasons for overheating, the environmental issues are the most obvious and easiest to avoid: Don't use your laptop in full sunlight for extended periods; don't leave it in a closed car on a sunny day; don't place it on or near extreme heat sources, such as radiators, hot air vents, and so on. Common sense, really--and the same advice that's in almost every owner's manual for almost all portable electronic devices. It's so obvious, in fact, we won't spend any more time on it.

The other two reasons--dead fans and dust and dirt--both cause reduced airflow through the laptop. You can look for and solve these problems the same way. Most times, you won't have to open the laptop's case, so there's no issue of voiding the warranty, and nothing that requires exotic tools or training. In fact, it's so simple a procedure, I'm amazed more people don't do it.