Recovering Windows Xp

Problem

Windows XP could not start because the following file is missing or corrupt:

 \WINDOWS\SYSTEM32\CONFIG\SYSTEM

Solution

 Insert the Windows XP startup disk into the floppy disk drive, or insert the Windows XP CD-ROM into the CD-ROM drive, and then restart the computer.
Click to select any options that are required to start the computer from the CD-ROM drive if you are prompted to do so.

 When the "Welcome to Setup" screen appears, press R to start the Recovery Console.

 If you have a dual-boot or multiple-boot computer, select the installation that you want to access from the Recovery Console.

 When you are prompted to do so, type the Administrator password. If the administrator password is blank, just press ENTER.

 At the Recovery Console command prompt, type the following lines, pressing ENTER after you type each 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

for further reading please visit

http://support.microsoft.com/default.aspx?scid=kb;en-us;307545