1. Insert the Windows XP installation CD into your CD/DVD-ROM drive. Restart your computer.
2. Press any key when you get a message prompting you to press a key to boot to a CD.

3. Press 'Enter' when the setup installation wizard starts.
4. Read the 'Windows License Agreement,' then press 'F8' to accept it.
5. Use your arrow keys to select the most recent installation of Windows XP that you want to repair.
6. Hit the 'R' key to select 'Repair.' This will restore the 'Win32 config' system files to your computer.