How to Replace Missing or Corrupt System Files on Windows XP

1. Start Windows. Log in using the 'Administrator' account, or an account with administrative privileges.
2. Click the 'Start' button, then click 'Run.' In the window that appears, type 'cmd' without quotation marks and hit 'Enter.' This will launch the Command Prompt.
3. Type 'sfc /scannow' into the Command Prompt, and hit 'Enter.' This will run the System File Checker, which will scan every Windows system file and replace those that are damaged. Be prepared to insert the Windows XP CD if prompted. When the process is complete, close the Command Prompt.