It really depends on whether or not it's deemed a product "fault" or an end-user error. I'm guessing that as long as you didn't abuse your Powerbook, that it really is some hardware issue. In this case, I suggest you call Apple in lieu of going into a retail store. The rep will likely be more responsive to your needs, and you'll be able to explain that the broken hinge is really affecting your ability to use the machine properly. Best of luck 🙂