procedure TForm1.Button1Click(Sender: TObject);
var 
 a : Array[0..MAX_PATH] of char; 
begin
 Memo1.Clear;
 GetWindowsDirectory(a, sizeof(a));
 Memo1.Lines.Add(StrPas(a));
 GetSystemDirectory(a, sizeof(a));
 Memo1.Lines.Add(StrPas(a));
end;