What does SFC.exe mean?

SFC.exe is the windows system file checker. It checks system files for corruption or unwanted changes. If sfc discovers that a protected file has been overwritten, it retrieves the correct version of the file from the %systemroot%\system32\dllcache folder, and then replaces the incorrect file. If %systemroot%\system32\dllcache folder is corrupted, you need to have the windows installation CD to replace damaged files. %systemroot% is usually C:\WINDOWS.