Computer Turns Off Without Warning

If your computer turns off without warning, it’s a sign that something is very wrong. Maybe your computer turns off while playing a game or maybe it turns off after a few minutes even when you are doing nothing.

There are several common causes of sudden power offs and a few more exotic causes. I’ll start with the common and move to the less common.

The Computer Turns Off Without Warning When It Overheats

The most common cause of a sudden power off is overheating. The BIOS program which resides on your computer’s motherboard is designed to power off your computer immediately if your computer gets too hot—typically higher than about 150C (300F). This helps protect your computer from heat damage.

One simple reason computers overheat is because they’re in hot rooms. If the temperature in your room goes above about 45C (110F), the fans on the computer may not be sufficient to dump the excess heat from the computer processor (CPU) or graphics processor (GPU). A simple solution (besides getting an air conditioner) is to take the case off of the computer so it can cool to room temperature much faster. Be careful doing this if you have pets or young children who might stick their limbs in the fans or on the hot parts of the computer.

If your room isn’t that hot, your computer could be overheating because its fans aren’t working properly. If your computer doesn’t make any noise when it’s turned on—especially after it has a few minutes to warm up—the fans probably aren’t working. (Note: some mini computers don’t have fans.) Turn off your computer, open up your computer case, and turn your computer back on to see if the fans are working. If they aren’t, you need to fix them yourself (usually by buying new fans), or you need to take the computer to a repair shop.

Sometimes the fans are working but the computer still overheats. This happens when you get too much dust inside the computer. Dust is a terrific insulator—dust is made primarily of cellulose, the same stuff they use for premium home insulation. The dust collects on your computer’s heat sinks and prevents the heat from moving from the CPU or GPU to the air so the fan can whisk away that heat.

Cleaning the dust of your computer takes only a couple minutes. Buy a can of compressed air from the supermarket, turn off your computer, remove the case, and clear out any dust.

If none of the tricks above fixed your problem, your computer probably isn’t overheating, so move to the next section.

The Computer Turns Off Without Warning During Brownouts

Have you ever noticed your lights flickering during a thunderstorm? That’s a brown out. Your computer is much more sophisticated than a light bulb and parts of it need constant power in order to work correctly. For example, your computer memory (RAM) needs a bit of electricity every 28 milliseconds or it will lose data.

High-quality computers with high-quality power supplies often include a small capacitor which acts sort of like a very short term battery during brownouts. It helps keep your computer functioning. Cheaper computers include smaller capacitors, so the computer turns off without warning during brownouts.

Note: some brownouts happen so quick you don’t see the lights flicker. But your computer notices them the same. Even if your computer doesn’t shutdown during a brownout, you can get some weird effects if you lose data from your computer memory or the CPU misses a beat.

If you get frequent brownouts, you canbuy a Uninteruptable Power Supply (UPS) for your computer which will keep the power on during a brownout and even a short blackout. Don’t buy the absolute cheapest UPS—they tend to wait too many milliseconds before turning on. Go for a mid-range UPS (about $100 in the U.S.).

The Computer Turns Off Without Warning When There’s A Virus

One way computer viruses hide from anti-virus software is by using space in your computer’s hard drive and memory which is dedicated to Windows itself. When Windows tries to access some of this space and discovers it’s already being used by the virus, Windows doesn’t know what to do, so often it will display a Blue Screen Of Death (BSOD) and become non-responsive. Sometimes it won’t even display the BSOD; the error will be so bad, the computer just turns off.

Obviously the fix for this problem is to remove the virus. You will need a current malware remover and some time. If that doesn’t fix your problem and you think you still have a virus, you will probably need to reinstall Windows.

The Computer Turns Off Without Warning When There’s A Wiring Fault

An electrical short—when the electrical current from two separate wires accidentally connects—can start a fire, so most modern electronics try to detect this problem and shut off instantly if they find it. If your computer turns off without warning, and you have none of the problems above, you could have a wiring fault.

Wiring faults are usually hard to detect and hard to fix. If you changed something physical in your computer shortly before you started having problems, change it back. Otherwise, you will need to bring your computer to a repair shop. Be warned: most repair shops probably won’t fix a wiring fault, or if they do, they will charge more than the cost of a new computer. You can also try some free hardware diagnostic tools to find the problem.

Normally, a wiring fault would persist and you wouldn’t be able to turn your computer on anymore. But sometimes a wiring fault only happens when the computer gets hot or when a particular component gets used. So your computer runs fine for a few minutes until the circuit gets shortened and then it shuts down without warning. Although having your computer turn off suddenly seems like a pain, it possibly saved your computer from going up in flames and burning down your house.

If you have a wiring fault on a removable component, such as a hard drive, you can replace just that component. But if the wiring fault is on the motherboard, you will probably need to replace the whole computer or just live with the fact that the computer turns off without warning.