System File Chacker (SFC /Scannow) prompts for XP SP2 CD & doesn't accept the Windows XP CD

You are prompted to insert a Windows XP SP2 CD when you try to run the System File Checker tool on a Windows XP SP2-based computer

SYMPTOMS
When you try to run the System File Checker tool (Sfc.exe) on a Microsoft Windows XP Service Pack 2 (SP2)-based computer, you may be prompted to insert the Windows XP SP2 CD. However, the System File Checker does not accept either the Windows XP SP2 CD or the original Windows XP CD.

Note You can install Windows XP SP2 either from the Windows XP SP2 CD or by downloading the SP2 files. To download the SP2 files, visit the following Microsoft Web site:
http://www.microsoft.com/windowsxp/sp2/default.mspx (http://www.microsoft.com/windowsxp/sp2/default.mspx)


CAUSE
This problem occurs because the System File Checker must verify the SP2 files against the originally installed files. However, the System File Checker does not recognize the Windows XP SP2 CD or the Windows XP CD.


RESOLUTION
To resolve the problem, use one of the following methods.

Method 1: Insert a Windows XP CD that has SP2 integrated
For more information about how to integrate software updates into Windows installation source files, click the following article number to view the article in the Microsoft Knowledge Base:
828930 (http://support.microsoft.com/kb/828930/) How to integrate software updates into your Windows installation source files


Method 2: Modify the registry to point to the Windows XP SP2 Setup files
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk. 1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Locate the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup
3. In the right pane, right-click ServicePackSourcePath, click Modify, type %windir%\ServicePackFiles, and then click OK.


REFERENCES
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
897128 (http://support.microsoft.com/kb/897128/) You may be prompted to insert a Windows XP Professional CD when you run the System File Checker tool in Windows XP Home Edition
885522 (http://support.microsoft.com/kb/885522/) System File Checker does not accept a network location that contains the installer CD when you use the scannow switch in Windows XP SP2 or in Windows Server 2003