How to Fix Windows 10 Not Booting

Before assuming the Windows software is corrupted, you must eliminate the possibility of a hardware conflict. One of the most frequent causes of a 'No bootable device found' error is a USB flash drive or an external hard drive plugged into the PC. In 2026, many BIOS and UEFI systems are configured to prioritize external storage for booting. If a non-bootable drive is detected first, the system will hang. Unplug every peripheral except for your monitor, keyboard, and mouse, then attempt a restart. This includes webcams, printers, and especially any SD cards left in the built-in card reader.

Next, inspect the physical health of your internal components if you are comfortable opening your case. A loose SATA cable or a M.2 SSD that has wiggled out of its slot can prevent the motherboard from seeing the boot drive. If you are using a desktop, try reseating your RAM sticks by removing them and clicking them back into place. For laptop users, ensure the battery has sufficient charge; sometimes a critically low battery prevents the system from initiating the boot sequence even when plugged in. If you hear a series of beeps when you press the power button, consult your motherboard manual for 'Beep Codes,' which identify specific hardware failures like GPU or memory errors that prevent Windows from loading.

Windows 10 includes an automated utility designed to fix registry errors and missing system files. To access this, you need to enter the Windows Recovery Environment (WinRE). Since your PC won't boot, you can trigger WinRE by turning your computer on and off three times in a row using the physical power button. On the third attempt, Windows should display the Automatic Repair screen. If this does not happen, you will need to boot from a Windows 10 installation USB. Once in the recovery menu, navigate to Troubleshoot > Advanced options > Startup Repair.

The tool will begin scanning your system for known issues, such as a damaged Master Boot Record (MBR) or a corrupt boot sector. This process can take anywhere from five minutes to half an hour depending on the speed of your drive. If the repair is successful, your computer will reboot automatically into the login screen. If you see a message stating 'Startup Repair couldn't repair your PC,' do not panic. This simply means the issue is more specific than what the automated tool can handle, and you will need to proceed to the manual command-line repairs or Safe Mode to resolve the conflict.

Safe Mode loads Windows with a minimal set of drivers and services. If your PC stopped booting immediately after you installed a new program or updated a graphics driver, Safe Mode is the best way to revert those changes. From the Advanced options menu in the recovery environment, select Startup Settings and then click Restart. Once the computer reboots, you will see a list of options. Press 4 or F4 to start your PC in Safe Mode. If you need internet access to download a repair tool, press 5 for Safe Mode with Networking.

Once you are in Safe Mode, the desktop will look different and the wallpaper will be black, which is normal. Go to Settings > Apps and uninstall any software you recently added. You should also check Device Manager by right-clicking the Start button. Look for any devices with a yellow exclamation mark, right-click them, and select Uninstall device or Roll Back Driver. This is particularly effective for fixing boot loops caused by incompatible display drivers. After making these changes, restart your computer normally to see if the boot issue is resolved. If the system still fails to start, the problem likely lies deeper in the boot configuration files.

When automated tools fail, you must manually repair the bootloader using the Command Prompt. Navigate to Troubleshoot > Advanced options > Command Prompt. This opens a high-level administrative terminal. The first command to try is bootrec /fixmbr, which repairs the Master Boot Record. If that finishes successfully, type bootrec /fixboot and press Enter. If you receive an 'Access is denied' error during the fixboot command, it is because your system is likely using a GPT partition with UEFI. In this case, you may need to use the bcdboot command to point the system back to your Windows directory.

To rebuild the entire boot list, type bootrec /rebuildbcd. This command scans all disks for Windows installations that are not currently in the Boot Configuration Data (BCD). If it finds an installation, it will ask if you want to add it to the list; type Y and press Enter. For systems that still won't budge, run chkdsk c: /f /r to scan the hard drive for physical sectors that might be corrupted. This command can take a long time, but it is essential for ensuring that the physical drive isn't the root cause of the file corruption. Once finished, type exit and restart the PC.

System Restore is a life-saver that allows you to roll back your entire Windows configuration to a point in time when it was working perfectly. This process does not delete your personal documents, photos, or files, but it will remove any applications and updates installed after the restore point was created. In the Advanced options menu, select System Restore. You will be prompted to choose a user account and enter your password. Once the wizard opens, check the box that says Show more restore points to see a full list of available dates.

Look for a restore point that was created a day or two before the boot issues started. Often, Windows creates these automatically before a major system update. Select the point and click Next, then Finish. Windows will begin restoring your system files. Do not interrupt this process, as it can take quite a while and involves moving large amounts of data. If the restore completes successfully, your PC should boot into Windows as it was on that specific date. This is one of the most reliable fixes for registry corruption or system-level errors that occur after a failed Windows Update in 2026.

Sometimes the software is fine, but the motherboard's firmware settings have changed. This can happen if your CMOS battery (the small coin cell on the motherboard) is dying, causing the BIOS to reset to default values. Restart your computer and repeatedly tap the Del, F2, or F12 key (depending on your manufacturer) to enter the BIOS/UEFI setup. Look for the Boot tab and ensure your primary hard drive or SSD is set as Boot Option #1. If you see 'Windows Boot Manager' as an option, make sure it is at the top of the list.

Additionally, check the SATA Mode or Storage Configuration. If your Windows was installed while the mode was set to AHCI and it somehow switched to IDE or RAID, Windows will crash with an 'Inaccessible Boot Device' error. Switching it back to the original setting will fix the problem instantly. You should also verify the Secure Boot and Legacy/CSM settings. Modern Windows 10 installations typically require UEFI mode with Secure Boot enabled. If your BIOS has reverted to Legacy mode, it will not be able to find the EFI boot partition on a modern drive, resulting in a failed boot sequence.

If all other methods fail, you may need to reset Windows 10 to its factory state. This re-installs the entire operating system but gives you the option to keep your files. From the recovery environment, go to Troubleshoot > Reset this PC. You will be presented with two choices: Keep my files and Remove everything. Choose the first option to preserve your data. Windows will then ask if you want a Cloud download or a Local reinstall. In 2026, the Cloud download is generally recommended because it fetches a fresh, updated copy of Windows from Microsoft's servers, ensuring you aren't reinstalling the same corrupted files that caused the boot failure.

Note that while your documents will remain, you will lose all installed programs and customized settings. After the reset, you will find a list on your desktop of all the apps that were removed so you can reinstall them later. If even a reset fails or produces an error, it is likely that your hard drive or SSD has suffered a permanent hardware failure and needs to be replaced. Before giving up, you can try to boot from a Live Linux USB to see if you can access your files and back them up to an external drive, as this confirms the hardware is still readable even if Windows cannot start.