Most likely you have seen a computer from some OEM manufacturer that comes with a pre-installed operating system. Typically no original Microsoft OEM CDs are provided. Instead the manufacturer wants you to create a system restore CD/DVD set or a recovery partition as a method to restore your system incase of corruption.

What if the only problem you were receiving was a couple of windows system files were altered due to a third party application and now windows recognizes that these files are not from their original source. Now the operating system is prompting you to run system file checker (WFP) to replace or update the incorrect driver versions of these files. But of course you have no CD/DVDs to provide XP to stop the prompting of theses Windows File Protection notifications that keep randomly popping up on your screen.

The OEM vendor always places the full installation of XP in an i386 folder located on your hard-drive minus the setup.exe which isn't needed for WPF/SFC (for license agreement reasons). In my case the i386 folder and the CMPNENTS folder for Media Center Edition were located in two different locations on the C drive. Every time I ran sfc /scannow it would prompt me for either CD 1 or CD 2 depending on what my SourcePath value equaled in the registry. Of course with this value it only allows me to specify one location for the installation files. Needless to say I was unable to completely run sfc without it asking for one or the other CD locations. Here is what I have done to circumvent this situation.

Firstly, identify the location on the local hard-disk of where the windows installation files are stored. For instance the path of the compressed windows setup files may be found in: C:\windows\i386 or C:\winnt\i386 or C:\i386 or C:\CMPNENTS (for Media Center Edition CD 2) Once familiar with where the OEM vendor has placed the compressed XP files you can then enter the system registry to make the necessary change.

1) In Start menu > run > regedit
2) Locate HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Curr entVersion\Setup
3) On the right hand side of the screen you should see a string called SourcePath. If you only have one location for these files which is typical of an XP Home or Pro installation. Change the SourcePath REG_SZ key to the location of your XP files found on your hard-drive. If you have multiple locations as for a Media Center Edition which contains two CD's, therefore two separate locations for the i386 information for Windows Media Center Extenders. Delete the SourcePath REG_SZ key. Create a Multi String Value instead. Name this value SourcePath. Then double click the SourcePath Multi String and under the value on a separate line type the individual path's pertaining to the locations of the XP source files. For instance:
C:\windows\i386
C:\CMPNENTS

Then carefully exit out of the registry.

Now re-run sfc /scannow and watch that it will now copy the appropriate files from the locations you have specified in the Multi-String and it should now no longer prompt you for providing the CD's when it finds an discrepancy among itself.