Okay, deep breaths. What about it isn't working? Is it not responding to input? Is the pressure sensitivity gone? Are there no lights/no indication of power? Is it moving the cursor but not detecting when you apply pressure? Check the cord for damage, check the nib on the stylus (try both ends, see if one responds and not the other if you have one that has two ends), try restarting the computer, reinstalling the drivers. Try a different USB port. That's all I can think of to try at this point, best things to try in order are trying a different USB port and checking the usb cable, trying the other end of the stylus (if this applies) restarting computer, reinstalling drivers.