How to Fix a Corrupted Windows XP Registry

There are times when Microsoft Windows XP will not start due to a corruption in the Windows registry. In order to recover from this corrupted registry, there are a few steps that must be followed. Taking these steps may not completely fix the problem, depending on the cause, but this will help recover lost files.

Difficulty: Moderate

Instructions

Things You'll Need:

• Windows XP start-up disk

Creating a Registry Back-up

1. Place the Windows XP start-up disk into the CD-ROM drive or into the floppy disk drive. Restart the computer.

2. Select options that are needed to start the computer using the CD-ROM if you are prompted.

3. Press "R" in order to start the Microsoft Recovery Console when the "Welcome to Setup" screen shows up on your computer.

4. Type in the administrator password when asked to do so. If there is no password with the administrator's account, simply press "Enter."

5. Type in the following lines, being sure to add a page break after each one.
   
   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
   
   del c:\windows\system32\config\system
   
   del c:\windows\system32\config\software
   
   del c:\windows\system32\config\sam
   
   del c:\windows\system32\config\security
   
   del 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 in the word "exit" on the screen to quit the recovery. Wait for your computer to restart.

Start Windows in Safe Mode

7. Choose "Start" or the Windows icon in the bottom left-hand part of your screen. Choose "Shut Down" or "Turn Off Computer" and then select "Restart" from the drop-down menu. Click "OK".

8. Press the "F8" key to start the computer in safe mode when you reach the start-up menu.

9. Select the safe mode option with your arrow keys and press "Enter." Run Windows Explorer when the system starts up. Select "Folder Options" from the "Tools" menu. Select the "View" tab.

10. Under "Hidden Files and Folders," check the box that says "Show hidden files and folders" and un-check the box that says "Hide protected operating system siles". Select "OK" or "Yes" if a dialog box comes up.

11. Open the drive where Windows XP is installed by double-clicking it. All files will then be shown.

12. Open the "System Volume Information" folder. This folder is a hidden folder, extremely protected and may appear in a lighter color than the rest of the folders.

13. View all of the folders' properties and check the time that they were created until you find one that was not created at the current time. Open that folder. It should be a folder with RPx underneath of it. This is a restore file.

14. Locate a "Snapshot" folder within the one you just opened. It will have "Snapshot" written on the end of the file name.

15. Copy the following files to the C:\Windows\Tmp folder.
    _REGISTRY_USER_.DEFAULT
    _REGISTRY_MACHINE_SECURITY
    _REGISTRY_MACHINE_SOFTWARE
    _REGISTRY_MACHINE_SYSTEM
    _REGISTRY_MACHINE_SAM

16. Rename all of these files in the same order as below.
    Change the _REGISTRY_USER_.DEFAULT file to DEFAULT
    Change the _REGISTRY_MACHINE_SECURITY file to SECURITY
    Change the _REGISTRY_MACHINE_SOFTWARE file to SOFTWARE
    Change the _REGISTRY_MACHINE_SYSTEM file to SYSTEM
    Change the _REGISTRY_MACHINE_SAM file to SAM

Delete Existing Registry Files and Copy System Restore Files

17. Start the Recovery Console again.

18. Type the following lines into the command prompt, being sure to make a page break after each line.
    
    del c:\windows\system32\config\sam
    
    del c:\windows\system32\config\security
    
    del c:\windows\system32\config\software
    
    del c:\windows\system32\config\default
    
    del c:\windows\system32\config\system
    
    copy c:\windows\tmp\software c:\windows\system32\config\software
    
    copy c:\windows\tmp\system c:\windows\system32\config\system
    
    copy c:\windows\tmp\sam c:\windows\system32\config\sam
    
    copy c:\windows\tmp\security c:\windows\system32\config\security
    
    copy c:\windows\tmp\default c:\windows\system32\config\default

19. Type "exit" and allow the computer to restart.

20. Click "Start" and then choose "All Programs" from the menu.

21. Select "Accessories" and double-click it. Next, click "System Tools."

22. Choose "System Restore" and then select the option that says, "Restore to a previous Restore Point."

Tips & Warnings

• Use the Automatic System Recovery or ASR that is built in to the Microsoft Windows XP operating system if the option is available before manually restoring your system. This is the method that Microsoft recommends before moving on to the steps in this article. If the Windows is installed to a folder besides the C:\Windows folder, you will need to change the lines accordingly.
• By changing or missing one word in the commands that are required, it is possible that you will interfere with the recovery process. Be sure to be precise when entering commands and to double-check that they are correct.

References

• Automated System Recovery Remedies
• Windows Registry Recovery