The power supply is usually the first culprit when your PC doesn’t turn on.
What if it’s completely healthy and your computer still doesn’t turn on?
Although the problem may be strange at first, solving it isn’t always as tough as it looks.
Read on as we help you identify the cause and fix this issue.
Computer Not Turning On, Power Supply Okay (Causes, Fixes)
Cause 1: The Basics
Sometimes the solution is right in front of you, but you ignore it because it sounds too simple.
Before moving on to more serious issues, make sure you rule out the following potential causes:
- Power cord. Ensure the power cable is functioning and healthy by physically inspecting it for signs of damage. Plus, make sure it’s firmly plugged into the wall outlet as it may come loose over time.
- Power supply switch. The power supply itself has an on/off switch, which is different from the PC’s power button. It’s located under or next to the PSU’s power output. Check if it hasn’t been accidentally switched off.
- Power outlet. Do you get electricity from a wall outlet? Plug the computer into a different outlet to rule out this possibility.
- Power button. You may not notice any visible faults in the power button, but the internal wirings may be loose or cut off. Open the case and inspect all the wires to ensure you’re not losing any connections.
- Surge protector. If you’ve plugged the system into a surge protector, make sure it isn’t faulty. You could plug other appliances into the surge protector or plug your computer into a wall outlet and see if you can turn it on.
- Fans. You may never suspect that faulty fans can create power issues, but they have a crucial job of cooling down the CPU and the entire system. If the CPU overheats, it will shut down on its own, so you may want to ensure all the fans, especially the CPU fans, are working properly.
Cause 2: The Monitor
The monitor is the device that displays images and texts processed by the computer’s video card.
Because its role is only to display information, it doesn’t occur to most people that the monitor may be the reason their computer won’t turn on.
However, sometimes checking the monitor is the best solution to what seems to be a booting problem.
If you’re sure about the health of your PSU, checking the monitor is the priority.
A. Cables Issues
Ensure the power and data cables are plugged in.
No matter which type of cable you’re using, it should fit properly on both ends.
Once you’ve checked the connection, see if your cables are healthy.
Run your fingers along with the cables and feel for tears.
If you want to be 100% certain that your cables are healthy, you need a multimeter.
This YouTube video tells you how to use the device to check your cable’s health:
B. Wrong Port
Most modern monitors have three ports for receiving data from your case: DisplayPort, HDMI, and USB-C.
On the other hand, older monitors come with a single 15-pin VGA port, and you may also find a DVI port on some monitors.
Since there are various ports on a monitor, you may have selected the wrong input source in your settings.
When this happens, your computer starts working properly, but you don’t see a picture since the monitor isn’t configured properly.
To make sure that doesn’t happen, let’s briefly go over the types of ports and what they look like.
HDMI is a popular format for transferring both audio and pictures with high-quality.
Its connector has 19 pins divided into five trapezoids, and it’s usually larger than a USB port.
They also have three sizes; the larger one (macro) is often used for computer monitors.
To distinguish HDMI cable, its name may be written on the port side.
The DisplayPort is a new addition to most monitors, which looks similar to HDMI, but it has 20 pins.
The port has a “DP” label to distinguish it from HDMI.
In addition to monitors, some laptops may come with a DisplayPort in one corner.
USB isn’t common in monitors, given its lower picture quality, but it exists in most to allow connecting peripheral devices.
USB-C ports are either rectangular or oval in shape, and they’re designated with an “SS” next to a trident consisting of an arrow, circle, and square.
F. Choosing The Right Input Source
Now that you can tell different ports apart see which one your monitor is connected to.
Open the settings menu on your monitor and check the source input in your monitor settings to see if it’s set to the right port.
There’s usually a menu button on the monitor’s panel.
You can also test different input sources to see if anything changes.
Sometimes, switching from HDMI to VGA or DisplayPort can do the trick, assuming you have the right cables.
G. Faulty Monitor
If you have access to another monitor, connect it to your computer and see if you get a picture.
You can also use a TV or projector.
All modern TVs and projectors support HDMI.
Conversely, you can connect your monitor to a laptop or another computer.
If the picture comes on, your monitor is fine, and you should look for other causes.
Otherwise, you need to have a technician look at your monitor.
Cause 3: Do You Hear A Beep Sound?
Once you’ve ruled out the monitor, it’s time to look for more serious issues.
This is especially the case if your computer makes a beeping sound as soon as you press the power button.
The beep is a warning that indicates you have a hardware failure.
Because the failure occurs before the video card has a chance to load, your computer can’t display any error information.
Instead, it uses various beeps to point you in the right direction.
Before you can interpret the code, you need to identify your BIOS manufacturer because each manufacturer has a different set of beeps defined.
Since your computer doesn’t boot, you can’t use software tools that give you information on your computer components.
Your only choice is to open up the case and locate the BIOS chip on the motherboard.
The manufacturer’s name should be printed somewhere on the chip.
Once you know which company built your BIOS chip, you can do a quick Google search for their list of beep codes and the associated meanings.
In most cases, a single beep indicates a normal boot and that everything is fine—except Dell BIOS, where it means the BIOS itself is failing.
Multiple beeps are usually a sign of RAM or motherboard failure, while a continuous beep signals video card issues.
Finally, if you have an IBM or Insyde BIOS, you should pay attention to how many long and short beeps you hear because different combinations have different meanings.
Note: If you’re not sure how many times the BIOS beeps, don’t be afraid to restart your computer.
You’re very unlikely to cause more damage because the computer is designed to protect itself by automatically turning off.
Once you’ve figured out which component is causing the issue, it’s time to see if you can resolve it.
However, dealing with computer hardware requires technical expertise, so it’s best to leave it to a professional if you don’t know what you’re doing.
In addition, you should note that if you have a prebuilt system and it’s the first time you want to open the case, you may void your warranty by doing so.
Therefore, it’s better to contact the manufacturer and review your options.
Cause 4: The Motherboard
The motherboard is the platform that connects all the components in your computer together.
If it doesn’t work properly, your CPU, GPU, RAM, and hard drive can’t communicate.
In most cases, your computer won’t turn on.
If the root cause is a faulty motherboard, you’ll have a harder time diagnosing and fixing the issue because of the wide range of components connected to it.
Any of these components could develop faults and cause a power issue for the entire system.
That’s why you should inspect each component individually.
Remember to switch off the computer and unplug all power cords to avoid possible shocks.
The first thing you should check is whether you’ve added any new components to the motherboard recently.
Disconnect that component and try turning on the computer.
All cables and connections on the motherboard need close inspection as even the smallest fault in these connections can create a wide range of problems.
These cables also include the SATA, IDE, and SCSI connections, which you should disconnect one by one, turn on the computer, and see what happens.
Cause 5: RAM
The RAM is one of the first components on the motherboard that can develop problems and cause power issues.
However, the RAM problems may not be as serious as you’d think and simply be due to built-up dirt and debris or loose connections.
PCs and laptops have different places for seating the RAM sticks, so you may want to refer to the manufacturer’s website or user manual to locate the RAM.
Disconnect the RAM sticks by pushing the clips that hold the RAM modules in place until the module pops out.
While removing the RAM modules, be careful not to touch any of the metal contacts on the bottom.
Now, inspect the modules carefully for dust and debris build-up, blowing on them and the slot, and using compressed air if necessary.
After cleaning the slots and the RAM modules, you can reseat them, which shouldn’t be a problem because the retaining clips sit inside the slots easily.
You should hear a clicking sound without exerting much pressure.
Now, plug the power cord into the wall outlet and see if you can turn on the system.
Remember not to touch anything inside the case, or you may electroshock yourself.
If reseating the RAM sticks doesn’t help, you can’t rule out faulty RAM yet.
That’s because one of the RAM modules may be faulty, and you need to find it through the process of elimination.
Here, you need to remove each module one by one, turn on the computer, and see what happens.
If the computer turns on, the RAM stick you’ve removed is the culprit.
If it doesn’t, you should remove another stick.
If you finally find out that a faulty RAM stick is behind the power issue, you should replace it with a new one.
Cause 6: Other Components
As mentioned, other components that may be faulty, indicated by beeps, are GPU and CPU.
Again, you should look for faulty connections or dust and debris by physically inspecting these parts and reseating them.
However, if they have internal issues or need replacing, you need to consult a technician.
If you have access to a spare GPU or CPU, or you could borrow from a friend, connect them to your PC and see if it turns on.
This way, you can make sure the components have internal issues and need replacing.
What If There’s No Beep?
If there’s no beep, you need to continue the elimination process to find the culprit.
Here are some other things that may have gone wrong, preventing the computer from turning on:
1. Expansion Cards
Expansion cards are the electronic circuits that allow you to add more components to your system.
It’s another component that can prevent your computer from turning on normally if it’s not functioning well.
Much like RAM, you should inspect it for dust, debris, loose connections, or other faults.
You need to go through the same processes for cleaning and reseating it.
After locating the extension board, which is usually on the case, unscrew and remove it.
Remember to handle the board with care, holding it with both hands, and not touching its electronic parts.
Examine all parts and look for any signs of damage, dirt, or dust build-up.
Inspect the slots and blow compressed air inside them to clean them.
Before connecting the expansion slot, you could turn on the PC and see if it boots up without the expansion cards installed.
If it does, you can be sure that the card is faulty and replace it with a new one.
Otherwise, reseat the card and look for other problems.
The Complementary Metal-Oxide Semiconductor (CMOS) is a chip inside the computer that stores information, especially the BIOS.
If it’s faulty, the computer can’t turn on or boot up.
You may want to give it a try and see if it helps.
You can rule out the possibility of a faulty CMOS by resetting it, which you can do in different methods.
The most straightforward way is to use the Reset button next to or under the power button on the case.
To reset CMOS using this button, unplug all the cords and hold this button for ten seconds.
Then, plug in the cables and turn on the computer.
Alternatively, you could reset CMOS via that motherboard reset button found on modern systems.
To use this option, after unplugging all the cords and pressing the power button for a few seconds to drain all charges inside the system, open the case.
Look for a button labeled as “Clear,” “CLR,” or “Reset” on the motherboard.
Ground yourself, push the button, and hold it for around ten seconds.
Plug the cords and turn on the PC.