Other Problems with sfc

Source
#1
Has the CD Drive's drive letter changed (perhaps by the addition of another hard drive, partition, or removable drive) since Windows XP was first installed? If so, simply edit the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Setup\SourcePath to reflect the changed drive letter.
After you restart the computer, WFP and sfc /scannow uses the new source path instead of prompting for the Windows XP installation CD-ROM
#2
Has the registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Setup\SourcePath got an incorrect entry? The SourcePath entry does NOT include the path location till the I386 folder. It completes one folder ahead to reach the I386 folder.
Example:
If the I386 directory is at C:\I386, the SourcePath value would be C:\
#3
If the problem persists and you have the correct path for your I386 folder then the I386 folder is corrupted. To solve this problem copy I386 folder from the CD-ROM to your system restart the system and then
perform sfc /scannow again.
#4
You do not have an XP retail CD with an I386 folder on it. If you have a restore CD from your PC manufacturer then you may have to explore the CD to find the folder.
#5
You still keep being prompted for the XP CD yet you have done all in this article! There is another setting in the registry that may be causing the problem. Navigate to:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SourcePath
Make sure the entry here is the same path to the I386 folder as used above.
#6
Systems administrators can enforce security policies that may include changes to the Windows File Protection settings. You will need to speak with your network administrator about this, but it is important to bear in mind when Windows starts up, the Windows File Protection service synchronizes (copies) the WFP settings from the following registry key:

HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Windows File Protection

to the following registry key: 
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
Therefore, if any of the following values are present in the HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Windows File Protection key, they will take precedence over the same values under the HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon key.
This will not effect scannow sfc so much, but WILL make an impact if any of the other sfc.exe "switches" have been used! (More about these at the end of this article.)
#7
When you run scannow at logon you do not get a progress bar... This can easily be remedied by adding a new DWORD: SFCShowProgress to the registry key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
the values available are: 0 = disabled, 1 = enabled