bought a used powerbook g4 where can i get a start up disc

Hi TJ, & welcome to the forums! 🙂

We need a bit more info to get started.

If you don't know the model, find the Serial# & use it on one of these sites, but don't post the Serial# here...

http://www.chipmunk.nl/klantenservice/applemodel.html

http://www.appleserialnumberinfo.com/Desktop/index.php

How to find the serial number of your Apple hardware product...

http://support.apple.com/kb/HT1349

OK, could still be 3-4 different models...

To find out more remove the Battery from the machine and the tag inside it will reveal the rest of the specs:

So this machine is a 1.33 Ghz, 256 mb of Ram on the main logic board, 60 gb Hard drive, Combo DVD/CDRW, and an Airport Extreme Card

http://www.everymac.com/systems/apple/powerbook_g4/stats/powerbook_g4_1.33_12.ht ml

It's doubtful, but you can call Apple Customer Support 1-800-767-2775, provide the Serial Number and specifications of the Mac, and for a fee, a replacement set of system discs (if available), can be ordered.

However, the discs will be for the original version of OS, that was pre-installed, when the Mac was manufactured.

 Cheers, Tom 😉