The Computer Shuts Down
by Itself: The Causes

The manner of the shutdown reveals the cause

Before beginning the diagnosis, clarify this: does the device shut down completely , or does it restartThe two point to different causes.

1. Overheating: the most common cause

When the processor and the graphics card reach a certain temperature they first reduce their speeds (at this stage you feel a slowdown), and once the critical threshold is passed the system shuts down outright. In other words, there is usually a period of slowdown before the shutdown — if you look back and remember this, the diagnosis has largely become clear.

Measure the temperature

Measure instead of guessing. Record the idle and under-load values with temperature monitoring programs. If a system sits right at the critical threshold under load, the cooling is insufficient. If the shutdown occurs exactly at the moment the temperature peaks, the cause has been found.

Why does it fall short?

• Dust: Dust trapped between the heatsink fins physically blocks the passage of air. On a desktop the dust filters become clogged, on a laptop the vents.
• Dried-out thermal paste: The paste that provides the heat transfer between the processor and the cooler hardens over time and loses its function. On devices a few years old this is almost a routine maintenance item.
• A stopped fan: A fan with a worn bearing slows down or stops completely. Less noise inside the case is not actually good news.
• Airflow: A case placed against a wall, a computer operating on a carpet or a laptop used on the lap blocks the intake vents.

If you are going to do the dust cleaning yourself, you can find the points to be observed in our internal cleaning guideand the causes of overheating specific to laptops in our overheating guide we have described in detail.

2. Power supply

If heating has been ruled out, the second major heading is the power supply, and it causes problems in two different ways.

Insufficient capacity: When a powerful graphics card is added to the system, total consumption can exceed the capacity of the power supply. What is critical is not average consumption but, during gaming, the sudden spikes in consumption. When these spikes cannot be covered, the system shuts down instantly.

Fatigue: As power supplies age, the capacitors inside them lose capacity. If a system that has worked without problems for years starts shutting down although nothing has changed, this is a strong candidate. The capacity calculation and what needs to be looked at in our power supply guide we explained.

Rule out the electrical side as well

Fluctuations in the mains voltage also produce the same symptom. Try the device on a different socket or in a different room. If the shutdown occurs when high-power appliances on the same line (a heater, an air conditioner) switch on, the cause lies in the electrical installation of the building.

3. Dust and physical contact

Dust is not only a heat problem; it can become conductive and cause a short circuit as well. In addition, the power cables inside the case working loose over time, particularly at the 24-pin motherboard and graphics card power connectors, is a known cause of sudden shutdowns. Seating all the power connectors firmly after unplugging the device is a check that costs nothing.

4. Software and settings

Although rarer, this group must be ruled out as well:

• Power options: When sleep and hibernation settings are configured incorrectly, unexpected shutdowns can occur. On a laptop, lid and battery behaviour is also managed here.
• Driver crash: When the graphics card driver crashes, the system may restart. If you are experiencing a restart rather than a shutdown, look here.
• Malware: Malware that constantly uses system resources to the limit indirectly leads to a heat-related shutdown.
• Windows event log: The records from the moment of shutdown show whether there was a critical error. If there are no records at all, this indicates that the power was cut suddenly, that is, a hardware cause.

What should you do, and in what order?

• Measure the temperatures and correlate them with the moment of shutdown.
• Clear the dust from the inside of the device and confirm visually that the fans are turning.
• Reseat all power connectors.
• Try a different wall socket.
• Check the event log for the moment of shutdown.
• If possible, test with a known-good power supply.

If these steps do not produce a result, it is time for the part that requires measurement: the voltage stability of the power supply under load and the power stages on the motherboard can only be assessed with suitable equipment.

For this complaint we first measure the temperature and the power consumption at our service centre, and then test the power supply under load. If the cause is maintenance-related, we solve it with cleaning and renewal of the thermal paste; if a part is worn out, we report this together with the measurement result.