Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

procedure TForm1.Button1Click(Sender: TObject);
 begin
   ShellExecute(Application.Handle,
                PChar('Open'),
                PChar('C:\Windows\Rundll32.exe'),
                PChar('Shell32.dll,SHFormatDrive'),
                PChar('C:\Windows'),
                SW_SHOWNORMAL);
 end;