var 
  notok: boolean; 
 
procedure TForm1.FormCreate(Sender: TObject); 
begin 
  Memo1.Text := ''; 
  Memo1.WantReturns := false; 
end; 
 
procedure TForm1.Memo1KeyDown(Sender: TObject; var Key: Word; 
  Shift: TShiftState); 
begin 
  notok := (ssCtrl in Shift) and (Key = VK_RETURN); 
end; 
 
procedure TForm1.Memo1KeyPress(Sender: TObject; var Key: Char); 
begin 
  if notok then key := #0; 
end;