Code:

procedure TForm1.Button1Click(Sender: TObject);

var hn: HWnd;

begin

hn := FindWindowEx(FindWindowEx(FindWindow('Shell_TrayWnd', nil), 0, 'TrayNotifyWnd', nil), 0, 'TrayClockWClass', nil);

if hn <> 0 then

   ShowWindow(hn, SW_HIDE); //Bye,bye,Baby

end;

Code:

procedure TForm1.Button2Click(Sender: TObject);

var hn: HWnd;

begin

hn := FindWindowEx(FindWindowEx(FindWindow('Shell_TrayWnd', nil), 0, 'TrayNotifyWnd', nil), 0, 'TrayClockWClass', nil);

if hn <> 0 then

   ShowWindow(hn, SW_SHOW); //Hello, again

end;

Code:

function ShowTrayClock(bValue: Boolean) : Boolean;

var

TrayWnd, TrayNWnd, ClockWnd: HWND;

begin

TrayWnd  := FindWindow('Shell_TrayWnd', nil);

TrayNWnd := FindWindowEx(TrayWnd, 0, 'TrayNotifyWnd', nil);

ClockWnd := FindWindowEx(TrayNWnd, 0, 'TrayClockWClass', nil);

Result := IsWindow(ClockWnd);

if Result then

begin

   ShowWindow(ClockWnd, Ord(bValue));

   PostMessage(ClockWnd, WM_PAINT, 0, 0);

end;

end;

// Example to hide they clock:

procedure TForm1.Button1Click(Sender: TObject);

begin

  ShowTrayClock(Boolean(0));

end;