I presume this machine is the subject ( PowerBook, Mac OS X (10.2.x) ).
Is the reset disk you mention the Install Disk that came with the PowerBook when new?
How did you attempt to get it to work?
Have you made any upgrades to OS X 10.2?
Keep this manual handy for future reference
Ideally you want to get it to start with an install OS X disk and run disk utility and reinstall the OS X if no repairs are possible. One problem is that OS X 10.2 is not familiar to very many current Mac Users so they shy from questions.
Will it boot in Safe Mode? See
What is Safe Boot, Safe Mode? (Mac OS X)
Takes a while to run, but it usually "fixes" problems.
Resolve startup issues and perform disk maintenance with Disk Utility and fsck