How to Fix a Computer That Won’t Turn On

Edited 1 week ago by ExtremeHow Editorial Team

TroubleshootingComputersPowerHardwareWindowsMacDevicesPerformanceSettingsRepair

Facing a computer that won't turn on can be a frustrating experience, but don't worry; many problems can be fixed with a few simple troubleshooting steps. This guide will detail a detailed, step-by-step process to help you diagnose and fix problems that prevent your computer from turning on.

1. Check the power supply

The first and most obvious step to take when your computer won't turn on is to make sure it's getting power. Here are some steps to verify this:

• Make sure the power cable is securely connected to both the wall outlet and the power supply unit (PSU) on the back of the desktop computer or the power input on the laptop.
• Check if the power strip or surge protector (if you're using one) is turned on. Many power strips have a switch or reset button.
• If the computer is connected to a power strip, try plugging it directly into a wall outlet.
• If you have a laptop, check that the battery is properly installed and that the charger lights are on. In some laptops, removing the battery and then plugging it in can sometimes reset the power circuitry.

2. Inspect the power button

Sometimes the power button itself may be the culprit. Here's what you can do:

• Press the power button firmly. If it doesn't click, it may be stuck.
• On some computers, especially desktops, the power button may be disconnected or broken. If you have access to internal components, you can start the computer manually by shorting the power switch pins on the motherboard.

3. Look for an error code or beep

Many computers have built-in diagnostics that can help figure out what's wrong:

• If your computer is beeping or has lights flashing instead of turning on, refer to your computer's manual for a list of error codes, as these may indicate specific hardware problems.
• Write down any beep patterns or error messages you see on the screen and look them up on the manufacturer's website.

4. Check the monitor or display

If your computer appears to turn on, but nothing appears on the screen, the problem may be with the monitor or display:

• Make sure all cables connecting the monitor to the computer are securely connected.
• Try using another monitor or connecting it to the television to see if the display is the problem.
• For laptops, connect to an external monitor to see if the laptop screen is damaged.
• Adjust the brightness settings, and make sure the monitor or laptop screen is not accidentally set to too low brightness.

5. Remove external hardware

Peripherals can sometimes cause conflicts during startup:

• Disconnect all external devices, such as USB drives, printers, and external hard drives.
• Try turning on the computer with only the keyboard, mouse, and monitor connected.

6. Reset or replace the CMOS battery

The CMOS battery saves all BIOS settings, and a malfunction can sometimes cause boot problems:

• Open the computer case and locate the CMOS battery on the motherboard. It is a small, round, silver battery that looks like a coin.
• Remove the battery carefully and wait for about 5-10 minutes. When the battery is out, press the power button to drain any remaining power.
• Reinsert the battery or install a new battery, then try turning on the computer again.

7. Check the internal hardware connections

Loose or improperly seated internal components can prevent the computer from booting:

• Open the computer case and check that all cables connecting to the motherboard, including power cables and data cables, are secure.
• Make sure the RAM modules are seated properly. You can remove and reinsert the RAM sticks to make sure they are firmly in place.
• Check that the GPU (graphics card) and other expansion cards are properly seated in their slots.

8. Test the Power Supply Unit (PSU)

The power supply unit is important in providing power to all the components in a desktop computer. Here is how to test it:

• If you have another matching power supply or a power supply tester, you can use these to check if the PSU is functional.
• Make sure the PSU fan is spinning when you press the power button. If the fan doesn't spin, the PSU may be bad.
• You can also use a paperclip to jumpstart the PSU. To do this:

  1. Make sure the computer is turned off and unplugged.
  2. Locate the 24-pin motherboard connector.
  3. Insert one end of the paperclip into a green wire pin (pin 16) and the other end into a black wire pin (ground).
  4. Re-plug the PSU and switch it on to see if the PSU fan spins.
  
  This is a sign that the PSU can at least deliver power, but it is still not delivering power to all the hardware properly.
  

9. Check for overheating

Overheating may cause the computer to shut down and not restart:

• Make sure all fans inside the computer, including the CPU fan, GPU fan, and case fans, are clean and spinning properly.
• Check for dust accumulation and clean it using a can of compressed air.
• Make sure there are no obstructions in the computer vents and that the computer is in a well-ventilated area.

10. Check the motherboard

If the CPU, RAM, and PSU are working correctly, the problem may be with the motherboard:

• Look for any visible damage such as burnt components or leaking capacitors. Capacitors are small cylinder-shaped components, and if their top is bulging or leaking, they are faulty.
• Check the POST (Power-On Self-Test) LED indicators on the motherboard, if available. These LEDs can provide codes to help diagnose problems. Refer to the motherboard manual to learn what these codes mean.
• Remove and reinstall the CPU to ensure it is seated properly, and be sure to reapply thermal paste if you removed the CPU cooler.

11. Software Troubleshooting

If the hardware is working properly, the problem may be software related. Here are some steps that can be followed:

• If the computer turns on but cannot boot into the operating system, try accessing the BIOS/UEFI settings immediately after turning on the power:
  • Accessing BIOS settings typically requires pressing the F2, F10, Del, or Esc key while the computer is turned on (check your computer's manual for the exact key).
  • Reset BIOS settings to default: There is usually an option called "Load Default Settings" or similar.
• Try booting into safe mode:

  For Windows:

  • Turn on the computer and press F8 repeatedly before the Windows logo appears. Select "Safe Mode" from the Advanced Boot Options menu.

  For macOS:

  • Turn on the Mac and immediately press and hold the Shift key until the login window appears. Release the key when you see the Apple logo.
• Run the repair or recovery tool:

  On Windows, you can use Windows installation or recovery media to boot and select "Repair your computer" on the setup screen. Follow the on-screen instructions to attempt a repair.

  On macOS, use the built-in Recovery mode by pressing Cmd + R during boot to access macOS Utilities. From there, you can use Disk Utility to repair your disk or reinstall macOS if needed.

12. Seek professional help

If all else fails, and you've tried all of the above, it's probably time to seek professional help:

• Take your computer to a reputable repair shop where technicians have the tools and expertise to diagnose and repair more complex problems.
• If the computer is still under warranty, contact the manufacturer for assistance and possible repair or replacement services.

Conclusion

It can be challenging to deal with a computer that won't turn on, but by working systematically through these steps, you can often identify and resolve the problem. From ensuring proper power connections to checking for faulty hardware or software issues, this guide covers the most common causes and their solutions. Maintaining a calm and methodical approach will make the troubleshooting process more manageable and increase the chances of fixing the problem.

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