Running SFC without a CD ROM

If you run sfc /scannow and get prompted to insert a CD,
there are a couple of changes you might need to make.
Slipstream your copy of WindowsXP with the latest service pack you have applied.
Once these files are on your hard drive, you can simply make a few registry changes to point to those locations.
Start Regedit
Go to the follow locations and change the path to wherever you copied the source files.
Code:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\ServicePackSourcePath
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\SourcePath
the last one might not be necessary
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SourcePath