Why Does My PC Randomly Turn Off: 10 Reasons for Crashes

One of the most annoying problems you can face is your computer turning off randomly. You can be in the middle of some critical office presentation or close to your objective in your favorite game when your PC shuts down without warning.

There are a lot of reasons that may cause this to happen. The most common ones come as no surprise; overheating and power shortage. The components of your system are designed to shut the PC if there is a chance of damage.

So if you ask yourself why my PC randomly turns off, this comprehensive guide should help you find the answer (fingers-crossed).

So Why Does My PC Randomly Turn Off?

There are several reasons why your PC can turn off randomly. I will cover each one in detail.

1. Overheating Components, Including CPU, GPU, or PSU

One of the main culprits in random PC shutdowns is overheating. Three main parts, CPU, GPU, and PSU, can overheat and turn the PC off randomly.

The CPU and the GPU have internal heat protection mechanisms: thermal throttling and complete shutdown. Both of these components can get hot for a few reasons:

  • Insufficient or Bad thermal paste
  • Defective heatsink
  • Inadequate airflow
  • Accumulation of dust

Each of these problems can raise the operating temperature of your components.

You can keep a tab on the temperature of your core components in several ways.

CPUs Often Suffer From Overheating Issues

CPU is the biggest culprit that often gets overheated due to insufficient airflow or thermal paste.

You can check its temperature using free-to-use third-party software called CoreTemp or RealTemp.

What is the Safe Idle CPU Temperature 2
Image: RealTemp Showing the CPU Temperature

You can see above the minimum and maximum operating temperatures of my CPU. These numbers are ideal.

These utilities also show you the distance to TJMax temperature. TJMax temperature is where your CPU will start to throttle (reduce performance) seriously or even shut down your system throttle (reduce performance) or even shut your system down.

If your operating temperature crosses 90°C, then there is a high chance that an overheating CPU is causing your PC to shut down randomly.

GPU and PSU Can Also Overheat

In addition to the CPU, your PSU or if you have a dedicated graphics card with insufficient airflow can also be the culprit of your PC shutting down randomly.

Like with the CPU, you can keep a tab on GPU temperature using either of two free third-party software GPU-Z or MSI Afterburner.

gpu z temperature main
Image: GPU Z Showing GPU Temperature

PSUs are a bit trickier. There is no software you can use to monitor the temperature of your PSU.

However, you can check physically. If you see dust accumulated or the PSU fan isn’t working, there is a high chance that the PSU is overheating.

Additionally, a slight touch of a hand on the PSU can tell you whether it is exceedingly hot. Usually, a PSU is pretty cool to touch. Of course, please ensure your PC is disconnected from the wall socket before you feel the PSU with your bare hands. Even then, be very careful.

If you have a handheld IR Thermometer Gun, then you can use that to check the temperature.

Solution to Overheating

You can monitor your CPU and GPU temperatures if you encounter these signs.

If you observe high temperatures, you can: perform thermal repasting, improve the airflow, and install a better cooling system!

If the insides of your desktop are neat and clean without any signs of dust accumulation and if the CPU or the GPU cooler fan is working effectively, then thermal paste degradation can be the culprit.

If the PC shuts down and doesn’t turn on immediately when you try afterward, you should check the PSU for defects. It is also possible that the PSU is not giving out enough wattage for your system; in this case, consider replacing it.

2. Did You Perform a Recent Overclock?

Did you perform a recent overclock of your CPU or GPU? If so, this can raise the temperature of the components and destabilize them.

Overclocking should only be performed with proper guidance or adequate system cooling.

A bad overclock can damage your components beyond repair.


Could you bring your CPU and GPU back to default clocks? You can get your CPU back to its default clock speed by resetting the motherboard to factory default BIOS settings (remove the CMOS battery for 5 seconds and put it back in).

I explain this further in the following article:

Also Read:

3. Insufficient PSU / Power Surges

PSU comes in different wattage ratings ranging from 300W to 1200W and more.

If you have built a system that utilizes more power than the PSU can deliver, then that would naturally cause your PC to shut down.

In addition, the PSU has some safety mechanisms against anomalistic situations such as earth faults.

Most PSUs’ built-in function turns the PC off if any electrical surge or an earth fault is detected.

Finally, an old, worn-out power supply unit can cause your PC to shut down randomly.


If the issue is an insufficient wattage supply, it is time to upgrade your power supply unit.

You can use free tools to calculate your power supply requirement. I am listing two below:

4. Malfunctioning or Not Properly Connected Hardware Components

Every PC part is integral for the PC to function properly. Elements like the motherboard, the RAMs, the disks, etc., must work simultaneously for the system to operate.

If a critical component fails, the system will start at all, or you will often see a Blue Screen of Death.

Why Does My PC Randomly Turn Off
Image: Blue Screen of Death (BSOD) – a standard error caused by malfunctioning hardware.

Various reasons, such as issues with the motherboard, improper connection of components, etc., can cause BSOD. One of the main culprits is the RAM.

The operating system relies heavily on the RAM to store temporary data before and after processing. If the RAM or the slot is defective or not inserted correctly into the slot, you can experience abrupt system crashes with the BSOD (blue screen of death).

Another main component is the disk. It does not matter what kind of disk you have the operating system on; SSD, HDD, or NVMe M.2; in case of a defect in the disk or the SATA cables connecting it to the motherboard or a faulty M.2 slot, the operating system will crash.

BSOD is also a hallmark error of a failing hard drive.

Poorly connected dedicated graphics can also prevent your system from randomly turning off or not starting.

A majority of the dedicated graphics cards not only have to be placed into an x16 slot on your motherboard, but they also have to be connected with additional power supply cables.

graphics card connected
You must ensure all the power connectors on the graphics card are connected to PCIe cables from the PSU.

Also Read: What are PCIe Cables Used For? 


If you suspect the issue lies with the hard disk drive, test your PC with another hard drive or test your hard drive on a different PC to see if the problem persists.

If you have two RAM sticks, take one out and test your PC with another.

Also, is a defective port not causing the issue?

For that, try plugging your hard drive and your RAM sticks into a different slot. So, for instance, if you have four RAM slots on your PC and two RAM sticks, try taking the RAM sticks out and putting them in the free slots.

If you have a dedicated graphics card, please ensure it is plugged into the FIRST PCIe x16 slot on your motherboard and all the power is connected to the cables.

Also Read: Does it Matter Which PCIe x16 Slot I Use?

5. Viruses and Malware

Of course, one of the most dreaded issues that one can face.

A virus is one of the few causes of system failures and data loss. These small pieces of code can damage files, corrupt programs, erase data, and steal information, to name a few. Malware is a specialized version of a virus designed to destroy data and steal information.

If you don’t have an anti-virus installed or have one that needs to be updated, then one of these might sneak into the system and wreak havoc.

The virus can infect integral operating system files, slowing the system down. Once the virus destroys some of the most crucial files of the operating system, the PC may even shut down randomly with or without a blue screen of death.


The only solution against viruses is to install an anti-virus and update it with the latest signatures.

Often people download and install an outdated version of anti-virus software and never bother to update its signatures.

Since new viruses are born almost every day, you must keep your anti-virus software always up to date.

Once you have downloaded, installed, and updated trusted anti-virus software, scan the system thoroughly, and delete any suspicious files.

It is worth noting that prevention is better than cure. Hence, avoid any pirated data and third-party applications from unknown sources. Please don’t access new hard or flash drives without running them through an anti-virus scan.

Many trusted anti-virus software such as McAfee, Norton, Kaspersky, Avast, etc. However, even the Windows built-in Virus And Threat Protection utility is more than sufficient for overall protection. 

6. A Dead CMOS Battery

A dead CMOS battery is one of the most common causes of a motherboard malfunctioning.

Remove the CMOS battery for 5 seconds and then put it back in.

All motherboards have CMOS batteries. These batteries power the CMOS chip, which stores the real-time clock and the BIOS settings.

A dead CMOS battery means that your BIOS will not work, and if your BIOS does not work, your motherboard can experience all kinds of issues, including your PC randomly turning off.

If you often experience your PC not starting at all or one of the hardware malfunctioning randomly, reset CMOS by removing the battery for 5 seconds and then putting it back in or replacing it with a new one.

The CMOS battery is a CR2032 lithium coin cell battery.

Read in Detail: Why Do Motherboards Have Batteries?

7. Outdated Drivers

The device drivers are dedicated files that help the OS control a specific component. The manufacturer of components rolls out updates every once in a while so that they work correctly.

Windows has an automated system for detecting and installing new driver updates through its Windows Update utility.

Outdated drivers for any module can cause it to crash or stop working altogether.

Additionally, any obsolete drivers can create vulnerabilities and system instability. If an integral component such as the GPU stops working, the system becomes unstable and shuts down to avoid damage.


A simple way of keeping the drivers updated is to run the automated Windows Update utility. This method is time efficient as you do not have to search individually for every driver for your component.

Windows updater
Image: Windows Update Utility

The Windows Update Utility searches for newer drivers for all the connected components and updates the Windows with more recent patches and fixes.

You can access the Windows Update utility by typing “Windows Update” in the search bar.

8. Connected Peripherals Could Be Causing the Issue

For reasons unknown, there are some instances where the connected peripherals, such as the mouse, keyboard, flash drives, external hard drives, printers, etc., can cause system crashes.

The issue could be the driver, USB ports, or the connected component malfunctioning.


Remove all the peripheral components and start your system. See if the problem persists. If not, re-introduce each peripheral element one by one until you find the culprit.

9. Your OS has Become Corrupted Beyond Repair

If, either accidentally or due to a malicious virus, your OS has become corrupted beyond repair, then that can most certainly lead to crashes and your PC randomly turning off.


You will need to run the Windows repair utility, or you may have to format your drive and do a fresh Windows install.

10. You Have a Bad CPU or Motherboard

Finally, suppose you have tried everything and ensured that the rest of the critical components, such as the GPU, RAM, Hard Drives, and PSU, are functioning correctly. In that case, there are no driver issues, and your PC is clean from any viruses, so your motherboard or CPU may be dead.

This is one of the most dreaded issues you can face. The only solution here would be to test your CPU on a different motherboard (with a compatible CPU socket) or test the motherboard with a different compatible CPU.

If the problem of the PC randomly turning off persists, then this can help you verify whether the problem exists with the motherboard or the CPU.

I have written comprehensive guides on this topic which you can check:

Final Words

If you’re wondering why your PC randomly turns off, please don’t worry; you are not alone. In most instances, this is a prevalent issue caused by something as simple as an overheating CPU.

If you forget to apply thermal paste or the CPU cooler isn’t working correctly, that can lead to overheating, which can shut your PC down randomly.

Besides overheating, a component not plugged in correctly, accumulation of dust (particularly inside the RAM and PCIe slots), driver issues, and viruses are other significant PC culprits randomly turning off.

Sometimes, a bad RAM stick, a dying Hard drive, or an improperly connected GPU can cause this issue.

In the rarest of instances, a dying CPU or motherboard can cause your PC to turn off randomly, and this, unfortunately, is the most dreaded issue that is very hard to fix.

Frequently Asked Questions

1. How can I check if my PC is overheating and causing it to randomly turn off?

To check if your PC is overheating, you can use software tools like Core Temp or HWMonitor to monitor your CPU and GPU temperatures. You can also physically inspect your PC to ensure that the fans are working properly, the air vents are not blocked, and the heatsinks are not covered in dust.

2. Can a failing power supply cause my PC to randomly turn off?

Yes, a failing power supply can cause your PC to randomly turn off. If your power supply is unable to provide enough power to your PC, or if it is faulty, it can cause your PC to shut down unexpectedly. You can test your power supply using a multimeter or a power supply tester to see if it is functioning properly.

3. How can I fix a software issue causing my PC to randomly turn off?

If a software issue is causing your PC to randomly turn off, you can try updating your drivers and operating system to the latest versions. You can also run a malware scan to check for any viruses or malware that may be causing the problem. Additionally, you can try performing a system restore to a previous date when your PC was functioning properly.

4. Can a faulty RAM module cause my PC to randomly turn off?

Yes, a faulty RAM module can cause your PC to randomly turn off. If your PC is experiencing random shut downs, you can test your RAM using software tools like MemTest86+ to check if there are any errors with your RAM modules.

5. Can a damaged motherboard cause my PC to randomly turn off?

Yes, a damaged motherboard can cause your PC to randomly turn off. A damaged motherboard can cause a variety of issues, including random shut downs. You can inspect your motherboard for any physical damage or bulging capacitors that may indicate a problem.

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