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Why Won't My Computer Turn On? - 7 Possible Reasons Why Your Computer Won't Turn On

Why Won't My Computer Turn On

Date First Published: 16th March 2023

Topic: Computer Systems

Computer Questions & Answers

Difficulty: Easy

Difficulty Level: 3/10

Learn about why your computer won't turn on in this article.

Sometimes, you might press the power button on your computer and it simply won't turn on. There are so many reasons why a computer might not turn on. This article is designed to help you troubleshoot issues that might be preventing your computer from turning on, not issues with it starting up (booting), so if your computer will start, but will display a blue screen error, then it is clear that it turns on and this article does not apply to your problem. Below are 7 possible reasons why your computer won't turn on.

1. Power Cord Not Connected Properly

The first thing you should do if your computer won't switch on is make sure that the power cord is connected properly. Obviously, if the power cord is not connected to the back of your computer properly, your computer won't be able to receive any power and won't turn on. Check that the cable is not loose by disconnecting and reconnecting the power cord and ensuring that it is properly plugged into the plug socket or extension lead. Also, check that the power switch of your computer is on as some power supplies have a power switch on the back.

2. Extension Lead Or Surge Protector Not Properly Plugged In

If you're sure that the power cord is connected properly and the computer still won't turn on, then the extension lead or surge protector might not be properly plugged in. Check that the extension lead or surge protector is correctly plugged into the outlet and that the power switch is on. You can test that the extension lead or surge protector works by plugging in a device that you know works, such as your lamp and seeing if it turns on. If not, then there is a problem with the extension lead or surge protector.

3. Bad or Damaged Power Cord

If you have checked that the power cord and extension lead or surge protector is connected properly and your computer still won't turn on, the power cord that supplies power to your computer might be bad or damaged. Try using another power cord and trying again.

4. Bad Power Supply Or Power Button

If you have followed all the steps above and your computer still won't turn on, then the issue is not related to your power cord, extension lead, or surge protector. This indicates that there is a problem inside your computer. If your computer still won't receive any power, your power supply might have failed. Verify that it is properly connected to the motherboard. You can also test it using a multimeter to check that it outputs the correct voltage. If it doesn't, it is likely that the power supply is bad and needs to be replaced.

There might also be a problem with the power button. If it doesn't push down very far or gets stuck, it is likely that the power button is bad and needs to be replaced. The power button has a cable which is connected to two pins on the motherboard and pressing it down will receive the signal to supply the computer with power and start it up. However, replacing a bad power button is a complex process.

5. Conflicting USB Devices

If your computer will get power, but won't turn on properly, one of your USB devices might be causing a conflict which is preventing your computer from starting. Before assuming that there are problems with a hardware component, try unplugging anything that is not necessary for the normal functioning of your computer, like webcams, speakers, USB headsets, and external storage devices. Try booting with just a keyboard and a mouse, or even without them if you think they are conflicting, and see if this resolves the issue. Sometimes, it might not be the device. It might be a port on a computer. For example, some computers might not properly start if something is plugged into the front USB port and need to be empty during the boot process.

6. Problems With Another Hardware Component

If your computer will get power, which is indicated by lights on your computer, but is not turning on properly, then there are no issues with the power supply. This indicates that another hardware component is failing. Each time your computer tries to turn on, it runs a power-on self-test (POST) to check that all hardware is working properly before starting the boot process. The computer will not continue to boot if any hardware components fail.

There are built-in tests that can help understand why your computer is failing to boot up. POST codes and beep codes are visual or audio signals that the motherboard manufacturer uses to communicate the results of internal hardware tests, which can help to determine any hardware issues that are preventing your computer from turning on.

Visual POST codes consist of two numbers that indicate the point the computer came across a hardware issue in the process of booting. This usually helps to identify the source of the problem. Most motherboards have a hexadecimal display that will show the code.

Beep codes are the audio equivalent of visual POST codes. If there is a problem with a hardware component that is preventing your computer from starting, you might hear a few beeps. These audio signals have exactly the same diagnostic functions as POST codes. For example, three beeps that repeat after a pause and happen when you power on your computer can indicate a problem with the system memory. Every motherboard manufacturer uses a different system of beep codes, so you should check your motherboard documentation to see if you can identify the issues.

To fix this issue, try to identify the source of the problem that is preventing your computer from booting up by paying attention to the visual POST code or beep code. You can search online or read your motherboard documentation. A hardware component could be loosely connected, overheating, or bad and need replacing. There is a chance that a hardware component has become loose, especially if you were recently working inside of it or if it was recently transported somewhere.

7. Bad Motherboard

If you are sure that it is not a problem with the power supply, and you are not getting a POST code, then there might be a problem with the motherboard. This is the last thing that you should check and it can be difficult to find the source of the problem as the issue could be anywhere in the circuitry. The motherboard communicates these problems and if it is bad or damaged, then you won't get a visual POST code or beep code. To resolve this issue, open the computer case and check the motherboard for problems, such as:

  • Cracks in the circuit board
  • Blown capacitors
  • Melted integrated circuit due to overheating
  • Broken pins or prongs for an integrated circuit

Although a blown capacitor can be replaced, the other problems above will most likely require the whole motherboard to be replaced. Without a properly working motherboard, no components can interact with each other and the computer won't turn on.

If you have tried everything above and have done everything you can to try and resolve the problems, and your computer is still not turning on, we recommend that you get professional help. If your computer is still under warranty, you should contact the manufacturer. If it has expired, you should find a computer repair shop in your area. They might be able to fix the problem. If you can't afford it, then it is best to completely replace the computer.


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