//这个方法绝对可以,index是你的任意行序列号。这个是绝对定位到行头,
方法比较丑,别扔东西!!哈哈,给分!
procedure TForm1.Button1Click(Sender: TObject);
var i:integer;
var Count:integer;
var Index:integer;
begin
        Index:=3;
        Count:=0;
        For i:=0 to Index-2 do
        begin
                Count:=Length(Memo1.Lines.Strings[i])+Count;
        end;
        Count:=Count+(Index-1)*2;
        Memo1.SelStart:=Count;
        Form1.ActiveControl:=Memo1;
end;