The "thing" you use as a reference source of information for SFC,
has to match the service pack level. If the system is installed to SP2,
then the CD used would be SP2. If the system is rev'ed to SP3, then
the CD used for SFC should be SP3 as well. They have to match.
(Similarly, if you want to do a repair install later, you should
have that slipstreamed CD handy as well. That can solve the >137GB
disk drive problem, depending when you bumped up the size of your
hard drive.) In my case, I keep D:\i386 as a copy of the CD, and
it's at the same Service Pack level as my installed system.
The article here, makes reference to two registry entries. Adjust
these as you see fit, until SFC runs.
http://www.updatexp.com/scannow-sfc.html
"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup
SourcePath D: <--- means D:\i386
"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\
ServicePackSourcePath C:\WINDOWS\ServicePackFiles <--- installed SPx
These may not be set by default on your system. When I tried SFC
on a previous install of WinXP, it kept asking for the CD as if it
didn't know where it was. I recollect having to edit two registry
entries, and then it did run. My config likely would match what
I've placed in the above two lines. Since I've reinstalled since then,
that registry info is gone (returned to defaults, whatever they are).
I'd have to re-test the above, and I have to do a backup first.
(I don't really trust SFC that much.)
I'm not at all convinced SFC does a good job. Yes, it occasionally
fixes a coincidentally damaged file (hard drive problem). But,
if you've been messing around, there was malware or whatever,
there's no guarantee this will fix it. It's not as good as a
repair install. It is not intended as a repair install (i.e.
put back all the SP2 files, tidy things up, polish the registry
or whatever). It doesn't do that. It's dumb and mechanical,
and compares a manifest to what it finds.
Here's a guy who keeps his two folders on a NAS. And pictures
are included of his registry settings. This would suggest
he's even gone to the trouble of moving the C:\WINDOWS\ServicePackFiles
off onto his NAS (network attached storage).
http://ask-leo.com/can_i_remove_the_servicepackfiles_folder_from_my_windows_folder.html
I don't actually have a C:\WINDOWS\ServicePackFiles on this machine,
and the reason for that, is the installer CD is a retail WinXP SP3
disc. So it was up-to-date at purchase. And no ServicePackFiles is
necessary. I probably don't need the second registry entry to complete
SFC in my current condition.
Did I mention backups ? Always a good idea, when dumb mechanical
scripts (SFC) are running, which have access to thousands of files.
One mistake and you could be non-bootable!
Good luck,
Paul