Botão Iniciar

Para habilitar:

EnableWindow (FindWindowEx (FindWindow ( 'Shell_TrayWnd', nil), 0, 'Button', nil), TRUE);

Para Desativar:

EnableWindow (FindWindowEx (FindWindow ( 'Shell_TrayWnd', nil), 0, 'Button', nil), FALSE);

Barra de Tarefas

function desabilitabarratarefa:string; // DESABILITA
var wndHandle : THandle;
wndClass : array[0..50] of Char;
begin
StrPCopy(@wndClass[0], 'Shell_TrayWnd');
wndHandle:= FindWindow(@wndClass[0], nil);
ShowWindow(wndHandle, SW_HIDE); // This hides the taskbar
end;

function abilitabarratarefa:string; // HABILITA
var wndHandle : THandle;
wndClass : array[0..50] of Char;
begin
StrPCopy(@wndClass[0], 'Shell_TrayWnd');
wndHandle:= FindWindow(@wndClass[0], nil);
ShowWindow(wndHandle, SW_RESTORE); // This restores the taskbar
end;