procedure TForm1.WMHotKey (var Msg : TWMHotKey);
begin
if msg.HotKey = zkratka1 then ShowMessage('Byla stisknuta kombinace Ctrl + A');
if msg.HotKey = zkratka2 then ShowMessage('Byla stisknuta kombinace Ctrl + B');
end;

procedure TForm1.FormCreate(Sender: TObject);
Const MOD_CONTROL = 2;
VK_A = 65;
VK_B = 66;

begin
zkratka1:=GlobalAddAtom('Hotkey1');
RegisterHotKey(handle,zkratka1,MOD_CONTROL,VK_A);
zkratka2:=GlobalAddAtom('Hotkey2');
RegisterHotKey(handle,zkratka2,MOD_CONTROL,VK_B);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
UnRegisterHotKey(handle,zkratka1);
UnRegisterHotKey(handle,zkratka2);
end;