Why on earth would you reformat? That is always a terrible idea and never solves anything.
By "downloaded games", what do you mean? Homebrew or pirated games? If the later, I advise you read the rules of the forum.
If you mean homebrew (which I will assume you do), you could try a game based exploit (there's a load of them, more info here: [
wiisixtyfour.webs.com]), might work better than LetterBomb for you. Before trying that, make sure you go back through the last few days and check them for the letter.