New Wacom Pen Isn't Reacting To Tablet Vise Versa?

Okay. So I just bought a new intuos4 pen for my intuos4 tablet because the last pen was lost. As I try to use it with extreme excitement (YAY!), I find that the pen is unresponsive (BOOO). So, my question is why is it doing this (or not doing this rather), and what can I do to make it function?