Your computer contains set of registries and system files for smooth and uninterrupted PC running. When any of the system files get deleted or registries got corrupted, you may face bunch of error messages or sometime complete system failure. One such error is “windows\system32\config\system” which may occurs due to of deleted system files, windows corruption, or hard drive failure etc. and will make your system unbootable. As results, you won't be able to access your stuff inside the system till you fix the error. See the below image to know how it looks like:

Computer won't boot

Windows could not start because the following file is missing or corrupt: \WINDOWS\SYSTEM32\CONFIG\SYSTEM”

If you are suffering from the same and desperately hunting for it's solution then you are at the right place as I'll describe here the most prominent causes behind this error and the easy steps to solve it on your own.

Why This Error?

As I described in above paragraph, your registries are the most sensitive parts inside the system and can be easily malfunctioned or damaged. Once your registries got corrupted, it makes their corresponding file (which is at the location Windows\System32\Config\system/software), unreadable. This system file can also be corrupted or deleted by viruses, human or the file itself got unstable by any unauthorized system operation and needs to be updated. Therefore, once the file is corrupted and next time you started the system, it won't boot up and gives an error as described in the image above.

What you can do to get it fixed?

The simplest solution is to replace the same file with an updated and non corrupted file from your Windows media disc or from the registry backup (if you had taken a backup of your system registries?

Here are the detailed steps on how you can do it manually:
  1. Insert your Windows installation CD into CD ROM and restart your PC.
  2. Follow the same steps as in the case of installing fresh Window except the screen appears after pressing 'F8' key, where you have to select 'R' key (to go the recovery console) instead of pressing 'Enter'.
  3. Select the targeted windows if you have dual booting operating system.
  4. Type the administrator password whenever asked. Leave it blank if you don't have any.
  5. Once you reached at the command prompt, type the following commands and press enter each time after typing a line:
    md tmp
    copy c:\windows\system32\config\system c:\windows\tmp\system.bak
    copy c:\windows\system32\config\software c:\windows\tmp\software.bak
    copy c:\windows\system32\config\sam c:\windows\tmp\sam.bak
    copy c:\windows\system32\config\security c:\windows\tmp\security.bak
    copy c:\windows\system32\config\default c:\windows\tmp\default.bak
    delete c:\windows\system32\config\system
    delete c:\windows\system32\config\software
    delete c:\windows\system32\config\sam
    delete c:\windows\system32\config\security
    delete c:\windows\system32\config\default
    copy c:\windows\repair\system c:\windows\system32\config\system
    copy c:\windows\repair\software c:\windows\system32\config\software
    copy c:\windows\repair\sam c:\windows\system32\config\sam
    copy c:\windows\repair\security c:\windows\system32\config\security
    copy c:\windows\repair\default c:\windows\system32\config\default
  6. Type ‘exist’ to navigate away from the black screen and restart your system. See if your system starts normally, but if not follow the next steps.
  7. Remove and connect your hard drive to another computer to take backup of your important data. Once you done with this again plug it back to your old computer and install a fresh copy of Windows to get back to your system normally and recover your data.