How to Fix the Error quot;File Is Missing or Corrupt \Windows\System32quot; so Windows Will Start

1. Boot your computer, insert the Windows XP CD-ROM in your optical drive and restart your machine. Select the option to boot from CD-ROM.
2. Press the 'R' key to start the Recovery Console. Type your Administrator Password, if prompted.
3. Type the following lines at the command prompt and press 'Enter' after each line:copy c:\windows\system32\config\system c:\windows\tmp\system.bakcopy c:\windows\system32\config\software c:\windows\tmp\software.bakcopy c:\windows\system32\config\sam c:\windows\tmp\sam.bakcopy c:\windows\system32\config\security c:\windows\tmp\security.bakcopy c:\windows\system32\config\default c:\windows\tmp\default.bakdelete c:\windows\system32\config\systemdelete c:\windows\system32\config\softwaredelete c:\windows\system32\config\samdelete c:\windows\system32\config\securitydelete c:\windows\system32\config\defaultcopy c:\windows\repair\system c:\windows\system32\config\systemcopy c:\windows\repair\software c:\windows\system32\config\softwarecopy c:\windows\repair\sam c:\windows\system32\config\samcopy c:\windows\repair\security c:\windows\system32\config\securitycopy c:\windows\repair\default c:\windows\system32\config\default
4. Type 'Exit' and press 'Enter,' to close the Recovery Console. The computer will automatically reboot.
5. Tap the 'F8' key when the computer reboots to bring up the black 'Boot to Safe Mode' screen. You May need to tap the key several times. Use the down arrow to select 'Safe Mode' and press 'Enter.'
6. Log in to Windows XP as the Administrator. Click the 'Start' button, select 'My Computer,' right-click on the 'C' drive and select 'Explore.'
7. Click on 'Tools,' click 'Folder Options' and select the 'View' tab. Scroll down to 'Hidden Files' and place a check mark next to 'Show Hidden Files and Folders.' Remove the check mark next to 'Hide Protected Operating System Files (Recommended).' Click 'Yes' to the confirmation prompt.
8. Right-click on the 'System Volume Information' folder and select 'Open.' Select the 'View' menu, and click 'Details' to show create dates and time on the sub-folders within the 'System Volume Information' folder.
9. Open any folder that begins with '_Restore' and that has a creation date before your current date and time. For example, '_restore{D852396E5-73Ef-56CG...}.'
10. Open one of the folders that begins with 'RP...' and open the 'Snapshot' folder. Copy and paste the following files to C:\Windows\Tmp:'_REGISTRY_USER_.DEFAULT''_REGISTRY_MACHINE_SECURITY''_REGISTRY_MACHINE_SOFTWARE''_REGISTRY_MACHINE_SYSTEM''_REGISTRY_MACHINE_SAM'Rename the copied files, in the C:\Windows\Tmp folder, as follows:Rename '_REGISTRY_USER_.DEFAULT' to 'DEFAULT'Rename ' _REGISTRY_MACHINE_SECURITY' to 'SECURITY'Rename ' _REGISTRY_MACHINE_SOFTWARE' to 'SOFTWARE'Rename '_REGISTRY_MACHINE_SYSTEM' to 'SYSTEM'Rename '_REGISTRY_MACHINE_SAM' to 'SAM'
11. Launch the Recovery Console and type the following lines at the command prompt. Press 'Enter' after each line:del c:\windows\system32\config\samdel c:\windows\system32\config\securitydel c:\windows\system32\config\softwaredel c:\windows\system32\config\defaultdel c:\windows\system32\config\systemcopy c:\windows\tmp\software c:\windows\system32\config\softwarecopy c:\windows\tmp\system c:\windows\system32\config\systemcopy c:\windows\tmp\sam c:\windows\system32\config\samcopy c:\windows\tmp\security c:\windows\system32\config\securitycopy c:\windows\tmp\default c:\windows\system32\config\default
12. Type 'Exit' and press 'Enter,' to close the Recovery Console. The computer will automatically reboot.
13. Log in to Windows XP as the Administrator. Click the 'Start' button and click 'All Programs.' Select 'Accessories' and click 'System Tools.'
14. Click 'System Restore' and select 'Restore to a Previous Restore Point.' Reboot your machine when the restore completes.