WD My Passport no longer works-it does not light up when plugged into the computer

My WD 500 My Passport external hard dive no longer does anything when I plug it into any computers. I have tried MACs and PC, both with working drives. I have also changed out the cord with a new one and no luck. It was working the other day and everything was fine, today when I attempted to see files nothing happens: no lights, sounds, nothing. PLEASE HELP! Irreplaceable files are on there :womansad:

Try to see if the drive appears on disk management ( disk utility if Mac )