That Windows does not Boot can become a real nightmare, especially when we need the computer for work, study, or simply for everyday use. Although it may seem like a critical problem, the truth is that there are multiple ways to recover the system without having to reinstall from scratch.
In this complete guide we show you all the possible causes (both software and hardware) that can cause your operating system to crash during startup, and how to troubleshoot them step by step. From the simplest to the most technical methods, here's everything you need to know to get your computer up and running again.
Why might Windows fail to boot?
Windows startup errors can be due to a variety of reasons. In many cases, they are software-related problems.: faulty updates, corrupted system files, drivers incompatible or even infections by malware. Other times the fault may come from something more physical: problems with the hard drive, RAM, or a connected peripheral.
It is also common for changes in the BIOS or in the boot configuration, such as having connected a drive Bootable USB, prevent Windows from properly accessing your file system.
Therefore, before embarking on a reinstallation, it is advisable to identify the cause of the problem. Listen to what the equipment does when it turns on, pay attention to error beeps, messages that appear on the screen or even the simple fact that the screen remains black, can give us key clues as to how to act.
Common reasons why Windows won't boot
If your computer won't load Windows, it could be due to any of these reasons:
- a device USB connected that interferes with starting, such as an external hard drive or a pen drive.
- Changes to the BIOS boot order, which try to start from another invalid medium.
- Master Boot Record Failures (MBR) or in the boot sector of the hard drive.
- Corrupted files or drivers after a critical or poorly executed update.
- incompatible drivers, especially graphics or network cards.
- Errors in the Windows Registry after modifications or failed installations.
- Viruses or malware that interfere with system startup.
- Hardware issues in the RAM, power supply, hard drive or motherboard.
These problems affect different phases of the system boot process, from the BIOS POST to loading the Windows kernel. Let's see how to detect when your PC freezes and how to fix it in each case.
How to know at which phase the boot stops
The Windows boot process follows a very specific sequence. Identifying at what stage your team is blocked is key to applying the right solution.The main phases are:
- BIOS/UEFI phase: The initial hardware check is performed. If it doesn't pass this phase, you won't even see the Windows logo.
- Boot manager: Bootmgr, or the Windows loader, appears here. If it fails, you'll see errors like "Bootmgr is missing" or "Operating system not found."
- Operating system loader: : Winload.exe or winload.efi is started, which loads the basic system drivers.
- Windows Kernel: The system begins loading essential drivers, services, and files.
Depending on where your computer is stuck (black screen, frozen logo, error 0x7B, etc.), you'll need to apply different solutions. Let's look at all the available ones.
Disconnect external devices to rule out conflicts
One of the most common reasons why a computer may not boot properly is interference from connected USB devicesThese peripherals may cause the BIOS to attempt to boot from them or cause driver errors during startup.
Disconnect everything that is not strictly necessary: external drives, pendrives, wireless keyboards or mice, printers, etc. Leave it with just the monitor, keyboard, and mouse. Turn off the computer, unplug the power strip if necessary, wait a few seconds, and turn it back on.
Also check if you have inserted any DVD or SD card that may be interfering.
Enter safe mode or automatic recovery
Windows 10 and Windows 11 They have a mechanism that, after three consecutive failed boot attempts automatically activate the recovery environment. From this environment (Win), you can access tools such as safe mode, startup repair, restore points, etc.
If it is not launched automatically, You can force it by holding Shift while clicking Restart from the lock screen, or using a Windows installation USB.
Once in the recovery environment, access:
- Solve problems → Advanced → Startup configuration
- Balance Restart and select “Safe Mode” or “Safe Mode with Networking”
If Windows boots in safe mode, but not in normal mode, it is very likely a conflict with drivers or software.
To solve the problem, it is advisable uninstall any recent programs or drivers that you've installed. You may also consider performing a system restore to a previous point where your computer was working properly.
Another effective option may be update the drivers you have installed If you have Internet access in Safe Mode, be sure to visit your hardware manufacturers' websites for the latest versions.
Restore the system to a previous point
If you were able to access safe mode, you can try restoring your system. System Restore allows you to revert changes made to system settings without affecting your personal files.. To do it:
- Go to Control panel → Recovery → Restart the PC.
- Choose Restore the PC and follow the instructions to choose an available restore point.
Restoring may take some time, but it can often fix boot problems caused by recent software changes.
If you cannot access safe mode or if the restore does not work, You can try to repair Windows startup using the installation media. to access system repair tools.
Windows Startup Repair from Installation Media
If you have a Windows installation USB, you can use it to perform a startup repair. This method is useful if you're experiencing issues with the MBR or corrupted system files. To perform the repair:
- Insert the installation USB and boot from it.
- Select the language and keyboard settings and click Next.
- Click on Repair equipment instead of installing.
- Accede to Solve problems → Advanced → Symbol of the system.
From the command prompt, you can run commands on the table:
- bootrec / fixmbr to repair the MBR.
- bootrec / fixboot to repair the boot sector.
- bootrec / scanos to search for Windows installations.
- bootrec / RebuildBcd to rebuild the BCD (Boot Configuration Data).
These commands can resolve critical boot issues that prevent Windows from starting. Make sure you type them correctly and press Enter after each one.
Once the repairs are complete, try restarting your computer without the installation USB. If everything went well, Windows should boot correctly.
If the problem persists, it may be time to consider a clean install of WindowsHowever, this should be the last option, as it will mean losing data on your hard drive if you don't back it up first.
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