A facelift for ''Hello''

Cook flew under the radar the first two weeks of semifinals, offering up so-so covers of ''Happy Together'' and ''All Right Now.'' But in week 3, he broke out with an emo version of Lionel Richie's 1984 pop-cheese ballad ''Hello.'' ''That was a very brave thing to do,'' Simon observed, ''and I loved it.'' Not surprisingly, risk-taking arrangements would become Cook's American Idol trademark.