In what way doesn't it work? Are you expecting a page to be printed when you push the "Print Screen" button, or is it not copying the image to the clipboard to be pasted into an open app? That button will not print a page for you, it merely copies the desktop to the clipboard. So if your problem is that it won't print, then there is no problem; that's not supposed to happen. If it isn't copying to the clipboard so you can paste it into Paint or Photoshop etc., then I'd say there's a big problem that I can't help you with.
Is it one of those extra keyed USB keyboards with too many functions that require a driver or something? If so, perhaps you need a new driver or a roll back or so. Did it work previously and now it just doesn't do anything?