uses ShellApi, FileCtrl; 
 
const 
  EigeneDateien: PChar = nil; 
  Arbeitsplatz: PChar = ''; 
 
function explorer(flr: pchar): boolean; 
var 
  win: string; 
begin 
  result := false; 
  setlength(win, max_path); 
  if (flr = nil) or (flr^ = '') or directoryexists(flr) then begin 
    setlength(win, getwindowsdirectory(pchar(win), max_path)); 
    if ansilastchar(win) <> '\' then win := win + '\'; 
    win := win + 'explorer.exe'; 
    if fileexists(win) then begin 
      if flr <> nil then flr := pchar('/e,' + flr); 
      result := shellexecute(0, 'open', pchar(win), 
        flr, nil, SW_RESTORE) > 32; 
    end; 
  end; 
  setlength(win, 0); 
end;

 
// drei Beispielaufrufe 
procedure TForm1.Button3Click(Sender: TObject); 
begin 
  if not explorer(Arbeitsplatz) 
    then showmessage('Fehler'); 
end; 
 
procedure TForm1.Button4Click(Sender: TObject); 
begin 
  if not explorer('C:\Programme\Microsoft Office') 
    then showmessage('Fehler'); 
end; 
 
procedure TForm1.Button5Click(Sender: TObject); 
begin 
  if not explorer(EigeneDateien) 
    then showmessage('Fehler'); 
end;