Just found out that you deleted the wrong spreadsheet? Forgot your Windows password? Don't despair. You can take care of these and many other goofs with the following tips. It's amazing how fast a single keystroke or mouse click can change your life. One false move, and bang! An hour's, day's, or even lifetime's work can slip away into digital oblivion. But not everything that disappears is lost forever. These tips will help you retrieve the seemingly irretrievable: from files long ago removed from the Recycle Bin, to hard drives you pronounced dead in years past, to text messages zapped from your cell phone's SIM card.