Title: Disable mouse and keyboard
Use BlockInput procedure to lock keyboard and mouse. This procedure with True parameter disables manipulators and with False parameter enables them.
procedure BlockInput(ABlockInput : boolean); stdcall; external 'USER32.DLL';
...
procedure TForm1.Button1Click(Sender: TObject);
begin
BlockInput(True);
Sleep(5000);
BlockInput(False);
end;