Computer Not Turning On, Power Supply Okay (Causes, Fixes)

When your computer won’t turn on, the most common problem is with its power supply.

What if your computer is perfectly healthy but still won’t turn on?

Although it may seem strange at first glance, it’s not always as difficult as it seems.

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Continue reading to learn how we can help you fix the problem.

Power Supply OK, but Laptop Doesn’t Turn On (Causes and Fixes)

Cause 1 : The Basics

Sometimes, the solution is right in front you but you ignore it because you think it’s too easy.

Before you move on to more serious problems, be sure to rule out these possible causes:

  • Power cord. You can inspect the power cord for damage and ensure it is working properly. It should be plugged in securely to the wall outlet, as it could become loosen over time.
  • Power supply switch. The on/off switch for the power supply is separate from the power button. It is located underneath or near the PSU’s output power. It should be checked to make sure it isn’t accidentally turned off.
  • Power outlet. Can you get electricity from a wall outlet? To rule out the possibility, plug your computer into another outlet.
  • Power button. Although you may not see any faults with the power button, the wiring may be damaged or loose. To ensure that you don’t lose any connections, open the case and inspect the wires.
  • Surge protector. Make sure the surge protector is working properly after you have plugged it in. It is possible to plug in other appliances or plug your computer into an outlet wall socket and test if it turns on.
  • Fans. Although you may not realize it, faulty fans can cause power problems and have an important job cooling the entire system. Overheating can cause the CPU to shut down by itself. You will want to make sure that all fans, including the CPU fans, work properly.

Cause 2 : The Monitor

Monitors are the devices that display images and text processed by the computer’s graphics card.

Most people don’t realize that the monitor’s primary function is to display information. This could be why their computer won’t turn on.

Sometimes, however, a monitor check is the best way to solve a booting problem.

You should check the monitor if you are certain about the health and condition of your PSU.

A. Cables Issues

Make sure that the power and data cables have been plugged in.

Whatever type of cable you use, it must fit correctly on both ends.

After you have checked the connection, check to make sure your cables are in good condition.

Feel for tears by running your fingers along the cables.

Multimeters are essential if you want to ensure that your cables remain healthy.

This YouTube video shows you how to use this device to check the health of your cable.

B. Wrong Port

Modern monitors come with three data ports: DisplayPort (HDMI), HDMI (USB-C) and USB-C.

Older monitors have a single VGA port (15-pin), and some may have a DVI port.

There are many ports on a monitor so you might have chosen the wrong input source.

This is when your computer will start working correctly, but you won’t be able to see a picture because the monitor isn’t properly configured.

Let’s take a look at the different types of ports to make sure this doesn’t happen.


HDMI is a very popular format for high-quality audio and picture transfers.

It has 19 pins, divided into five trapezoids. It’s typically larger than a USB port.

There are also three sizes available; the macro is used most often for computer monitors.

The name of the HDMI cable may be printed on its port side to distinguish it.

D. DisplayPort

DisplayPort, a new addition to most monitors. It looks very similar to HDMI but has 20 pins.

To distinguish it from HDMI, the port is marked with a “DP” label.

Some laptops come with DisplayPorts in the corners.


Despite the lower quality of the monitors, USB is not common. However, it can be used to connect peripheral devices.

The USB-C ports can be either rectangular or oval in form and are marked with an “SS” next to a trident that consists of an arrow and circle.

F. F.

You can now tell the difference between ports and see which monitor it is connected to.

To check if your source input is set correctly, open the settings menu of your monitor.

The monitor’s panel usually has a menu button.

To see if there are any changes, you can also test other input sources.

If you have the right cables, sometimes switching between HDMI and VGA or DisplayPort is possible.

G. Faulty Monitor

Connect another monitor to your computer if you have it.

A TV or projector can also be used.

HDMI is supported by all modern projectors and TVs.

You can also connect your monitor with a laptop or other computer.

If the image is on, it’s a good sign. You should investigate other possible causes.

Cause 3: Do You Hear A Beep Sound?

After you have ruled out the monitor it is time to investigate other serious problems.

This is especially true if your computer emits a beeping sound when you press the power button.

A beep signals that your hardware is failing.

Your computer won’t show any error information because the failure occurred before the video card had a chance to load.

Instead, it uses a variety of beeps that point you in the right direction.

You will need to identify the BIOS manufacturer before you can interpret this code. Each manufacturer has its own set of beeps.

Software tools that provide information about your computer’s components can’t be used because your computer won’t start.

The only option is to remove the case from the motherboard and find the BIOS chip.

On the chip, it should bear the manufacturer’s name.

Once you have the company that made your BIOS chip, you will be able to do a quick Google search on their list of beep codes along with their meanings.

A single beep is a sign that the boot is normal. This is except for Dell BIOS where it indicates that the BIOS is failing.

Multiple beeps can be a sign that RAM or motherboard is failing, while a continuous sound could indicate a problem with your video card.

You should also pay attention to the number of long and short beeps that you hear if your IBM or Insyde BIOS is on. Different combinations can have different meanings.

Note – If the BIOS beeps repeatedly, don’t panic and restart your computer.

It is very unlikely that you will cause additional damage as the computer is programmed to automatically turn off.

Once you have identified the problem, you can start to resolve it.

Computer hardware can be complicated and requires technical knowledge. If you don’t have the right skills, it’s best that you leave it to professionals.

You should also be aware that you could void your warranty if you use a prebuilt system, and you open the case for the first time.

It is better to get in touch with the manufacturer to discuss your options.

Cause 4 : The Motherboard

The motherboard connects all components of your computer together.

It won’t work if your CPU, GPU RAM, RAM, or hard drive don’t connect properly.

In most cases, your computer won’t turn on.

Because of the many components that are connected to the motherboard, diagnosing and fixing the problem will be more difficult.

Each of these components can develop faults that could cause an entire system to lose power.

This is why each component should be inspected individually.

To avoid potential shocks, remember to turn off your computer and unplug any power cords.

You should first check if you have added any new components to your motherboard.

Reconnect the component and turn on your computer.

It is important to inspect all cables and connections on your motherboard. Even the smallest problem can cause a lot of problems.

You will also need to disconnect the SATA, IDE and SCSI cables. Turn on your computer and you’ll be amazed at what happens.

Cause 5: RAM

The RAM is the first component on the motherboard to experience problems.

RAM problems might not be as severe as you think. They could simply be caused by dirt, debris, or loose connections.

Laptops and PCs have different locations for the RAM sticks to be seated. You may need to consult the user manual or manufacturer’s website to locate the RAM.

Push the clips holding the RAM modules in place to disconnect the RAM sticks.

When removing RAM modules, make sure you don’t touch the bottom metal contacts.

Check the modules for debris and dust buildup. If necessary, use compressed air to blow on them.

After cleaning out the slots and RAM modules, it’s possible to reseat them. The retaining clips fit easily inside the slots.

Without applying much pressure, you should hear a clicking sound.

Plug the power cord into the wall outlet. Now you should try to turn the system on.

You may electroshock yourself if you touch the contents of the case.

If the RAM sticks don’t work, it’s possible that you have faulty RAM.

This is because one of your RAM modules might be defective and you will need to identify it using the elimination process.

You will need to take out each module individually, then turn on your computer and watch what happens.

The RAM stick that you have removed from your computer is what causes the computer to turn on.

If it does not, you can remove another stick.

You should replace the RAM stick if you discover that it is defective.

Cause 6 – Other Components

Other components that could be defective, as indicated by beeps are CPU and GPU.

You should inspect the parts for any loose connections or debris and then reseal them.

If they are damaged or have to be replaced, it is best to contact a technician.

Connect a spare GPU/CPU to your computer and check if it turns off.

You can then check if the parts are in good condition and need to be replaced.

What if There’s no Beep?

You should continue to eliminate the source of the beep if it isn’t there.

These are just a few of the other possible problems that could have prevented your computer from turning on.

1. Expansion cards

Extension cards allow you to add additional components to your system.

If your computer isn’t working properly, it can also be a component that prevents your computer from turning off normally.

Similar to RAM, inspect it for dust, debris and other faults.

For cleaning and reseating the item, you will need to follow the same steps.

Once you have located the extension board (usually on the case), unscrew it and then remove it.

Take care of the board by holding it in both hands and not touching any electronic parts.

Take a look at all parts to see if there are any signs of dirt or damage.

To clean the slots, inspect them and blow compressed air into them.

You could try turning on your computer without connecting the expansion slots to see if the PC boots up.

If it does, it is possible to be certain that your card is defective and replace it with a brand new one.

If you don’t want to risk it, then reseat your card and search for other issues.


The Complementary metal-Oxide Semiconductor (CMOS) , a chip in the computer that stores information including the BIOS, is called a “CMOS” (Hyperbolic Metal-Oxide Semiconductor ).

The computer won’t turn on if it isn’t working properly.

It might be worth a try to see if it works.

Resetting the CMOS can be used to eliminate the possibility of a malfunctioning CMOS. There are many methods you can use.

You can use the Reset button located under or next to the power button to reset the device.

This button can be used to reset CMOS. Unplug all cords and hold the button for ten second.

Plug in the cables, and then turn on your computer.

Alternatively, you can reset CMOS using the motherboard reset button on modern systems.

After unplugging all cords, press the power button for a few seconds to drain any remaining charges, then open the case.

On the motherboard, look for a button that says “Clear”, ,” CLR,” or “Reset”.

Hold the button for approximately ten seconds, then ground yourself.

Turn on your computer by plugging the cords.

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