In Windows XP if you get the error:

Windows could not start because the following files is missing or corrupt
\WINDOWS\SYSTEM32\CONFIG\SYSTEM or \WINDOWS\SYSTEM32\CONFIG\SOFTWARE

you need to repair those files which are corrupted or missing. Follow next steps to fix that error:

1. Insert and boot from your WindowsXP CD.
2. At the first R=Repair option, press the R key
3. Press the number that corresponds to the correct location for the installation of Windows you want to repair. Typically this will be “1″
4. Enter in the administrator password when requested
5. Type
   

   cd \windows\system32\config

6. Depending on which section was corrupted:
   

   ren software software.bad or
   ren system system.bad

7. Depending on which section was corrupted:
   

   copy \windows\repair\system
   copy \windows\repair\software

8. Take out the CD ROM and type exit.

Tags | Howto, Windows, Windows XP