Registry's troubles hunting source files solved

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Windows 2000, XP and 2003 use a Registry setting to determine where to obtain installation files, and where Service Packs were installed from. The former is used for installations from CD, and the latter is used for when the system needs to automatically obtain updated files from the service pack, so the user doesn't have to provide the files manually.

There are many scenarios where you may need to manually edit where Windows expects to find its installation files. One of the most common is when Windows is deployed using files on a network share, which is then later taken offline. If you try to replace system files via the System File Checker (SFC) utility (i.e., SFC /SCANNOW), Windows will search in vain for the installation path and fail.

Other problems can occur if Windows was installed via a custom-built CD with a directory structure that's different from the manufactured CD. If you install with one and then try to add components with the other, Windows may not be able to find everything if you use SFC.

Windows keeps its installation source locations in the Registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup. (Note that in Windows 2000, the Registry path may use "Windows NT" instead of "Windows.")

Look for the following values to edit as needed:

• Installation Sources (REG_MULTI_SZ): This lists all of the possible locations for Windows to check for installation files, each on its own line. If you want to add new locations to check for installation files, provide them here. Network paths are allowed. (If you're using Windows 2000, you must use RegEd32.exe to modify this value.)

• SourcePath (REG_SZ): The default location where Windows checks for an installation CD. This is by default a path to the first CD-ROM drive (i.e., E:\), and can be changed to point to a new path or a directory share if needed.

• ServicePackSourcePath (REG_SZ): The default location where the last Service Pack was installed from. This is generally set automatically when a Service Pack is applied.

• ServicePackCachePath (REG_SZ): The location where Service Pack files are cached and held so they can be copied out as needed -- for instance, if new hardware drivers or system components are installed. This is generally set automatically. Windows 2000 may not use this; look for ServicePackSourcePath instead.)