"Computer turns on but won't boot - Causes and Solutions"

Like the user above, your computer might not be turning on properly. This can happen to the best of us. It's incredibly frustrating when you press the power button and are met with a black screen. Fear not!

To assist you, this comprehensive guide will walk you through the reasons why your computer turns on but won't boot, and it will provide solutions to get your system up and running smoothly, along with a backup option to protect your data from loss.

Why does a computer power on but not boot up?

Here's a list of possible reasons why a computer might turn on but not boot: CPU failure, BIOS issues, insufficient power supply, upgrade errors, beeping codes, peripheral problems, damaged components, software or hard drive issues, and so on.

Solving the problem of a computer not being able to start up

Now that you're familiar with the possible reasons why your computer turns on but doesn't boot, let's go through the steps to resolve the issue and get your computer functioning again.

• Solution 1: Check the Power Supply
• Solution 2: Inspect the Display
• Solution 3: Test the Computer's Temperature
• Solution 4: Listen for Beeps
• Solution 5: Disconnect All External Devices
• Solution 6: Reinstall All Internal Components
• Solution 7: Check the BIOS
• Solution 8: Boot into Safe Mode
• Solution 9: Update Windows
• Solution 10: Check for Hard Drive Damage

Solution 1: Check the Power Source

The most common solution is to check whether the power supply is working properly and providing enough juice to all of a computer's components. To test a power supply unit (PSU):

1. Turn off and unplug the power supply from everything except the main AC cable.
2. Find pins 16 and 17, located above the 24-pin connector. Take a paperclip for testing and bend it so that both ends can plug into pins 16 and 17.
3. Power on your computer and check if the PSU fan starts spinning.

Check the power supply

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Fix 2: Check the Display

Please check that your monitor is correctly connected to your computer, as a loose or faulty connection could prevent the PC from booting up.

Unplug the monitor from your computer, then turn it off and on again. If you see any diagnostic information on the screen, then the monitor has power and is capable of displaying content.

Fix 3: Check your computer's temperature

Overheating can cause startup issues, so it's worth checking your computer's temperature to make sure that it's not running too hot. Keep it cool enough to function properly. Here's how:

1. After turning on your computer, press the necessary key during startup, such as "F12," "F2," "Esc," or "DEL," to enter the BIOS or UEFI.
2. While in the BIOS or UEFI interface, you should be able to check your CPU temperature.

Fix 4: Check the Beep Sound

A beep code is a series of beeps that a computer makes to tell you that there's a problem with your PC's hardware. So, listening for beeps can help diagnose issues right away.

• Power on the computer and listen for beep codes during startup.
• Restart the computer multiple times, listening carefully to the beeps and taking note of the sequence.
• Identify the manufacturer of the BIOS chip on the motherboard.
• Refer to the troubleshooting guide specific to the BIOS manufacturer.

Fix 5: Disconnect all external devices

External devices like printers, flash drives, and external hard drives can interfere with booting. So the fix is to unplug them one by one and reboot to see which device is causing the problem.

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6. Reinstall all internal components of the computer

You'll want to ensure that all components inside the PC, like the GPU, RAM, and power cables, are seated correctly. Re-seating the components will re-establish all the connections.

• Turn off the computer, unplug all power cords, and open the case. • Remove the internal cables, power cord, memory modules, and expansion cards. • Reinstall these parts, making sure all connections are seated correctly.

Tip: Make sure you plug the VGA cable into the correct video card, not the video port on the motherboard.

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Fix 7: Check the BIOS

Incorrect BIOS settings can cause issues where your computer powers on but doesn't boot. Resetting the BIOS to its default settings might help. Here's how:

• Turn on your computer and press "F2" or the designated key until you see the "Enter Setup" prompt.
• Depending on your operating system, click the "Load Default Values" button and then press "F9" or "Alt + F" to load the default settings.
• Finally, press "Esc," select "Save & Exit" or "Exit," then hit "Enter" to save all changes and exit the BIOS setup screen. Your computer will automatically restart.

Check the BIOS settings

Fix 8: Start in Safe Mode

Entering Safe Mode can help you diagnose various issues and repair your operating system. Here's how:

1. Hold down the Power button and the "Shift" key, then click on "Restart." 2. Select "Troubleshoot" > "Advanced options." Choose "Startup Settings," then click "Restart." 3. After your PC restarts, you'll see several options. Press the number "4," "F4," or "Fn + F4" to begin restarting in Safe Mode.

Fix 9: Windows Update

Sometimes, Windows updates can cause conflicts. So if your computer won't start, you'll have to perform an Automatic Repair:

• Turn the computer on and off repeatedly by pressing the power button until you see the "Automatic Repair" screen.
• Select "Advanced options."
• Choose the "Startup Repair" option and follow the prompts.

Select "Startup Repair" from the new window.

Fix 10: Check if the hard drive is damaged

It's essential to check and fix corruption issues on your hard drive. You can do this using built-in Windows tools like and to automatically scan and repair your drive. Here's how: 1. **Using System File Checker (sfc):** - Press `Win + X` to open the Quick Link menu, then select `Command Prompt (Admin)` or `PowerShell (Admin)` if you prefer. - In the command prompt, type `sfc /scannow` and press Enter. This will scan your system files for any issues and repair them if necessary. 2. **Using Check Disk (chkdsk):** - Open Command Prompt or PowerShell as an administrator (same steps as above). - Type `chkdsk /f /r /x C:` (replace `C:` with the drive letter you want to check) and press Enter. The `/f` flag repairs file system errors, `/r` finds bad sectors and recovers readable information, and `/x` forces the drive to dismount before scanning. - If prompted to schedule the scan for the next reboot, type `Y` and press Enter. Your computer will run the scan when it restarts. Remember that both of these processes may take some time, especially if your hard drive is large. It's recommended to perform these checks during non-work hours or when you don't need your computer for an extended period.

Boot from the Windows installation disc, choose your time zone, language, and keyboard input. Click on "Repair your computer," locate the "Windows installation drive (usually C:)," and then click "Next." In the "System Recovery Options" window, select "Command Prompt" and type in the command, then hit "Enter." For the command "chkdsk C: /f/", replace "C:" with the letter of the drive where Windows is installed.

Expert tip: Back up your computer regularly to prevent data loss.

It is worth emphasizing here the importance of regular backups to guard against data loss in case of accidents.

Todo Backup Free is a comprehensive backup tool that helps you back up your system, important files, or entire disks in case of accidental loss or hardware failure. Backups can be saved to external hard drives, local drives, NAS devices, or cloud storage.

Moreover, you can perform incremental or differential backups. This way, it only backs up the changed files since the last backup, saving time and storage space. In case of an accident, you can easily and quickly restore your data. You're also free to set up a backup schedule and run backups on demand.

Finishing up

In summary, understanding the various reasons behind a computer powering on but not booting and taking the corresponding troubleshooting steps is crucial. Additionally, regularly backing up your data using a professional tool like Todo Backup can prevent data loss and ensure a smoother recovery in case of unexpected incidents.

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Frequently Asked Questions (FAQ)

1. Can a dead CMOS battery prevent a computer from starting up?

Though the CMOS battery only keeps track of the system's date and time, a drained one can also cause issues with your computer starting up. You might also notice other changes, like missing drivers.

How do I know if my computer power supply is failing?

A computer that shuts down unexpectedly or won't turn on at all is likely having a power issue, so that's a good place to start.

How do I know if my motherboard is fried?

If the motherboard is faulty, your computer won't power on at all, so you'll have no booting or powering up of any kind. Alternatively, your computer might turn on and off immediately without any warning.