StrList:TStringList;
  F : Textfile;
try
  StrList:=TStringList.Create();
  StrList.Add(Datetimetostr(now));
  if fileexists('C:\123.Txt')=0 then   //好像这里出问题
    StrList.SaveToFile('C:\123.Txt')
    else
      begin
          //F:=StrList.Text;
         AssignFile(F, 'C:\123.Txt');
          Append(F);
         Writeln(F, '123.Txt');
         Closefile(F); 
      end;
  finally
  StrList.Free;
  end;
//出问题了 帮修改 下