Why Does My Laptop Shut Off By Itself?

It happens to everyone, eventually. You’re happily surfing the net, chatting with friends or working on a term paper, when suddenly – ZAP! Your laptop shuts off by itself – the screen goes dark, the fans spin down, indicator lights wink out and suddenly you realise how quiet things are without the roar of those fans.

Nervously, dreading the result, you press the power button, hoping that your beloved laptop will spring back to life, but fearing that it’s beyond such simple remedies. Nothing happens. You try again; still nothing. You pace the floor as panic sets in, wondering who you know who might be able to help. After all a little while, you screw up your courage and try again – wonder of wonders, this time the machine powers up.

Trying to convince yourself that this whole ugly incident was just a one-off, you settle down at the keyboard and for a while all is well. Then, just like before – ZAP! Again and again, the cycle repeats, with the interval between each incident getting shorter each time. What is happening? Why is your trusty laptop tormenting you like this?

Laptops are complex devices, and there could, of course, be many reasons for this apparently vindictive behaviour. The most likely explanation, however, is that the machine is simply overheating. How does this happen? Why? And what can be done about it?

Heat is a natural side effect of any electronic device’s operation, your laptop included. As electricity passes through the device’s components, they become hot – in some cases, very hot indeed. This is what makes an electric heater work, and why an incandescent light bulb gives off light – the filament gets so hot that it glows.

Inside a laptop, however, the heat generated by its normal operation is not such a good thing. Delicate electronic components, such as the processor that drives your laptop, are sensitive to heat, and could easily become damaged if they get too hot. Since the processor is also one of the biggest sources of heat, laptop manufacturers devise ingenious methods of drawing the heat it generates away from the processor and expelling it from the case.

These methods usually involve a piece of metal called a heatsink, at least one fan and two or more ventilation holes in the laptop’s case. The heatsink, which is kept in physical contact with the processor, heats up as the processor gets hot. The fan(s) suck cool air from outside the machine’s case in through one of the ventilation holes, blow it over the heatsink and force it out through the other ventilation holes.

Heat from the processor is transferred to the heatsink, which, in turn, transfers it to the cool air as it passes over the heatsink on its journey through the case. The heat is expelled from the case with the (now warm) air. As long as the fan(s) can keep the heatsink cool, the heatsink will, in turn, keep the processor cool and all is well. If they cannot, the processor gets hotter and hotter until, to save itself from damage, the machine simply shuts down. This is what causes your laptop to shut off by itself.

Now we know the reason for the problem, we can start to look for solutions. The first thing to do is make sure that the vent holes (usually found on the sides or bottom of the laptop) are not obscured – if the fan cannot draw cool air in, or force warm air out, it cannot cool the heatsink. If you are using the laptop on a table or desk, make sure that papers and other clutter haven’t collected against the sides or bottom of the laptop, and that there is plenty of room for air to flow around it. If you are using it on a bed or chair, be aware that covers and cushions can easily cover the vents, as can thick carpet if the machine is being used on the floor.

If that doesn’t appear to be the problem, examine the vents carefully – are they clogged by dust? If so, clear the dust away with a soft brush. If that doesn’t help either, there may be a coating of dust on the heatsink, which prevents it from transferring heat to the air passing over it.

The easiest way to resolve this problem is to obtain a can of compressed air from a hardware store or online retailer. With air spray to hand, shut the laptop down, disconnect it from the power and other cables,and remove the battery. Carefully squirt compressed air into the inlet vent – you will probably hear the fan spin as the air passes through the machine’s case, and may well see a small cloud of dust puffed out of the outlet vent.

When you are satisfied that the you have removed all the dust that you are going to be able to remove using this method, wait a few moments then replace the battery, reconnect the power and any other cables and switch the machine on. In many cases, this will resolve the problem, and the machine should now operate normally.

In the event that it does not, it may be that the fan has failed or is failing, or is obstructed by some debris, preventing it from turning properly. Some models of laptop make it easy to access the fan(s) simply by opening a small hatch in the bottom of the machine’s case. However, most require you to completely remove the bottom (and sometimes the top) of the machine’s case before access to the fan is possible.

The steps required to dismantle the machine vary wildly from one model to another, and such complete disassembly / reassembly instructions are beyond the scope of this article. In many cases, service instructions will be available from the laptop’s manufacturer, if you feel sufficiently confident to follow them. If not, it may be worth consulting a qualified service engineer.

Even when your laptop is running normally again, it is worth paying attention to its ventilation requirements. Remember to keep the vents clear, and provide good air flow around and beneath the case. You might even like to consider purchasing a cooling pad for your laptop. These are small surfaces for your laptop to sit on, usually with built-in fans to help keep it cool, and sometimes other features too. While they are by no means essential, anything you can do to keep your laptop running at, or close to, it’s ideal operating temperature will help to keep it working reliably for longer.