Windows 11 wont boot suddenly

1. Check Boot Configuration​

1. Reboot using Windows 11 installation media:
   • Create a bootable USB with another PC using the Media Creation Tool.
   • Boot into this USB by entering your BIOS/UEFI and setting the USB as the primary boot device.
2. Repair Boot Files:
   When at the Windows Setup screen:
   • Select Repair your computer > Troubleshoot > Command Prompt.
   • Run these commands:
     
     Code:

     bootrec /fixmbr
     bootrec /fixboot
     bootrec /scanos
     bootrec /rebuildbcd

   • If /fixboot fails with “Access Denied,” try:
     bcdboot C:\Windows /s X: /f UEFI
     Replace X: with your EFI partition’s drive letter (identified with diskpart -> list vol).
3. Restart and see if Windows boots.

2. Confirm Disk Health​

• Boot again into the Command Prompt before Windows starts.
• Run:
  chkdsk /f /r C:
  Replace C: with the drive containing Windows. If issues are detected, chkdsk will attempt repairs.

3. Perform Start-Up Repair​

• Boot from your Windows installation USB.
• Choose Startup Repair (under Troubleshoot > Advanced Options).
• Let Windows diagnose boot-critical issues and attempt automatic resolution.

4. In-Place Repair Installation​

• Use the same ISO file you downloaded and mount it again on a healthy PC.
• Select Upgrade This PC from the setup program while ensuring you "Keep personal files and apps." This allows Windows to replace only the system files while preserving your data.

5. If Safe Mode Still Fails​

• Enter UEFI settings (Advanced Options > UEFI Firmware Settings) and:
  • Disable Fast Boot temporarily.
  • Ensure Secure Boot and UEFI are enabled.
• Use Windows Safe Mode Diagnostic:
  1. Restart > Hold Shift while selecting Restart > Troubleshoot > Advanced Options > Startup Settings.
  2. Select Enable Safe Mode with Command Prompt.

   sfc /scannow
   DISM /Online /Cleanup-Image /RestoreHealth

Additional Notes:​

• If the ISO file itself was problematic or corrupted, redownload it directly from Microsoft and ensure integrity using utilities like the command Get-FileHash.
• If startup repair and all else fail, performing a clean install may be a necessity. In such a case, back up your important data via live Linux USB tools or an alternate working Windows drive.