You can enable or disable file name completion for a particular invocation of CMD.EXE with the /F:ON or /F:OFF switch. You ...

You can enable or disable file name completion for a particular  invocation of CMD.EXE with the /F:ON or /F:OFF switch.  You can enable  or disable completion for all invocations of CMD.EXE on a machine and/or  user logon session by setting either or both of the following REG_DWORD  values in the registry using REGEDIT.EXE:        HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor\CompletionChar      HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor\PathCompletionChar            and/or        HKEY_CURRENT_USER\Software\Microsoft\Command Processor\CompletionChar      HKEY_CURRENT_USER\Software\Microsoft\Command Processor\PathCompletionChar    with the hex value of a control character to use for a particular  function (e.g.  0x4 is Ctrl-D and 0x6 is Ctrl-F).  The user specific  settings take precedence over the machine settings.  The command line  switches take precedence over the registry settings.    If completion is enabled with the /F:ON switch, the two control  characters used are Ctrl-D for directory name completion and Ctrl-F for  file name completion.  To disable a particular completion character in  the registry, use the value for space (0x20) as it is not a valid  control character.