Hvis en vigtig Windows-fil bliver slået ned af en virus eller på anden måde beskadiget, skal du gendanne den fra Windows-cd'en. Søg efter filnavnet på cd'en, og udskift det sidste tegn med en understregning.
For eksempel: Notesblok.eks_
If it’s found, open a command prompt and enter the command EXPAND, followed by the full pathname of the file and of the desired destination: EXPAND D:\SETUP\NOTEPAD.EX_ C:\Windows\NOTEPAD.EXE. If either pathname contains any spaces, surround it with double quotes.
If the file isn’t found, search on the unmodified filename. It will probably be inside a CAB file, which Win XP treats as a folder. Simply right-drag and copy the file to the desired location. In other Windows platforms, search for a file matching *.cab that contains the filename. When the search is done, open a command prompt and enter EXTRACT /L followed by the desired location, the full pathname of the CAB file, and the desired filename; for example: EXTRACT /L C:\Windows D:\I386\Driver.cab Notepad.exe. Again, if the destination or CAB file pathname contains spaces, surround it with double quotes.