CTRL + Z = Undo! You were working on a document the other day and made a big mistake. You messed up just about the whole thing and it took forever to get it back to the way it was. Is there a better way? Yes. First, if you make a mistake, hit CTRL-Z. In most programs, that will undo whatever it was that you just did. Bad thing is that many programs only give you one or two of these undos. Then you're stuck - or are you? One clever way to make sure you can always go back is to save your file frequently - especially...