What you will need to do is take your XP disc and copy the i386 folder to the your root drive.
then let the computer know where it is.
Here's how: (type
regedit in the Run box on the start menu)
By navigating
to:HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows/CurrentVersion/Setup
You will see various entries here on the right hand side.
The one we want is called: SourcePath
It probably has an entry pointing to your CD-ROM drive,(usually D

and
that is why it is asking for the XP CD. All we need to do is change it
to: C: Now, double click the SourcePatch setting and a new box will pop
up allowing you to make the change to the drive letter of your root
drive, probably C:
Now restart your computer and try sfc /scannow again!