[Страдалецъ]

И мой вариантик

Код:

Var
  Pass: String;
  PassLen,i: Integer;
begin
 Pass := ''; PassLen := 10;
 for i := 1 to PassLen
 do case Random(3)
    of 0: Pass := Pass + Chr(65+Random(26)); //Верхний регистр
       1: Pass := Pass + Chr(97+Random(26)); //Нижний регистр
       2: Pass := Pass + Chr(48+Random(10)); //Цифры
    end;
end;