System Restore
1. Go to 'Start,' and point to 'All Programs,' point to 'Accessories,' point to 'System Tools,' and then click on 'System Restore.'
2. In the 'System Restore' wizard that opens up, select the 'Restore my computer to earlier time' option and then click 'Next.'

3. Select a 'Restore point' to restore your computer to and then click 'Next.'
4. In the 'Confirm restore point selection,' click 'Next' to complete System Restore.
Recovery Console
5. Insert the Windows XP Setup CD into the CD drive, and then restart your computer.
6. When you see the 'Welcome to Setup' screen, press 'R' to start the Recovery Console.
7. If you have more than one operating system installed on your computer, select Windows XP from the displayed list.
8. In the Recovery Console, type the following lines one by one and then press Enter. Here we are assuming that Windows XP is installed in the 'D' drive. If Windows XP is installed in another drive on your computer, you replace 'D' with that letter.md tmp
copy D:\windows\system32\config\system c:\windows\tmp\system.bak
copy D:\windows\system32\config\software c:\windows\tmp\software.bak
copy D:\windows\system32\config\sam c:\windows\tmp\sam.bak
copy D:\windows\system32\config\security c:\windows\tmp\security.bak
copy D:\windows\system32\config\default c:\windows\tmp\default.bakdelete D:\windows\system32\config\system
delete D:\windows\system32\config\software
delete D:\windows\system32\config\sam
delete D:\windows\system32\config\security
delete D:\windows\system32\config\defaultcopy D:\windows\repair\system c:\windows\system32\config\system
copy D:\windows\repair\software c:\windows\system32\config\software
copy D:\windows\repair\sam c:\windows\system32\config\sam
copy D:\windows\repair\security c:\windows\system32\config\security
copy D:\windows\repair\default c:\windows\system32\config\default
9. Type 'exit' (without the quotation marks) to quit the Recovery Console, and then restart your computer.