The guitars blare a familiar tune and Kurt Cobain approaches the microphone, moppish hair covering his haunted eyes. But when the lyrics kick in, it's not the words to "Smells Like Teen Spirit" that come out, it's "You Give Love a Bad Name." Cobain, or at least his computer-generated likeness, can be made to sing the Bon Jovi anthem (and many other non-Nirvana songs) in "Guitar Hero 5." And that has his estate threatening legal action. The game features two Nirvana tunes among the 85 songs that come with the game. Once players successfully complete one of those songs, Cobain's...