Andrew Ridgeley was last seen four years ago as half of the bouncy pop duo Wham! His partner, George Michael (present here as background vocalist in a song called ''Red Dress''), went on to multiplatinum fame. Now Ridgeley, too, has a song on the charts: ''Shake,'' the second cut on this album, in which, to the tune of fake-raunchy rock & roll, he imagines he's shaking his sexy woman ''like a rag doll.'' Nothing in his eager, tiny voice convinces us he could ever do such a thing, though there is verve in his music and, thanks to his band, snatches of fine, snarly guitar. But you've heard it all a hundred times before. Ridgeley seems to have redefined himself as a kick-in-the-pants rock & roller, but his songs still come out sounding like manufactured pop.