My son gave me a used G4 with OS X 10.4 and OS 9(which version I don't know). I noticed java and a few other things weren't working and for some reason I thought I needed to switch to OS 9. Well, when I did that I got nowhere. An error message "unimplemented trap" turn off extensions and restart. I don't have any of the disk for the unit. Short of going to the nearest computer repair place and have some lovely gentleman take a bunch of money I dont have, what can I do?