I would bring it to a store. If you call applecare they WILL refund the call fee if there is a hardware problem but I still wouldn't chance it.
I would definitely recommend that you purchase Applecare for that powerbook to extend the warranty another 2 years (and get free phone support). My powerbook's optical drive bit the dust at 2.5 years, waaay beyond the original warranty. It would have cost 700 dollars to go through apple for replacement. Also, I have had the display on mine replaced once ($800), trackpad replaced once ($600), and power brick replaced once ($400). So I got my $230 worth for the applecare I purchased (it's cheaper with student discount).
Laptops get banged up, it's as easy as that, they inherently have higher failure rates compared with their big boxed bros because of this feature. So save yourself the trouble and buy applecare