PowerBook G4 freezing randomly

Question

My PowerBook G4 (1.67) has worked flawlessly for 2 years, but just a few days ago it began freezing randomly. It freezes completely, without warning or slowdown. I have to shut it off manually each time. Sometimes it freezes after running only a few minutes, other times it freezes after several hours of normal workload.
It doesn't seem to be related to anything I'm doing at the time, as each time it has been different circumstances. The last time it was idle with only iTunes running.
I am running OS 10.4.9, but the problem began before I installed the OS X update, so I know that is not the cause.
Is there anything I can do to further troubleshoot the problem before sending it in? Any clues as to what might be causing this?
Specs:
PowerBook 15" G4, 1.67
Memory: 768MB
PowerBook G4   Mac OS X (10.4.9)   15", 1.67Ghz

Answer 1

Welcome to Apple Discussions, BPMayer.
Apart from what has already been suggested by joeuu, it is possible that your problem may be either hard drive or logic board related. Certainly something to test for and, hopefully, rule out.
Therefore the first thing I would recommend is that you make sure any important data is fully backed up immediately. If you don't have an external backup drive (preferably a FireWire drive), then this is a very good time to get one.
Next try restarting from the original installer disc and then using Disk Utility to check the state of the hard drive. At the same time see what the SMART status (located at the bottom of the DU window) says. If it says anything other than "Verified" then the hard drive is the source of the problems.
Another thing to try is the Apple Hardware Test. This may reveal any problems with the internal hardware.
Unfortunately hard drive failures can, and do, happen fairly often with any computer that uses one as a storage device. Therefore it is a problem that can afflict any brand of computer, not just restricted to Apple, and (unfortunately) seems to be much more prevalent nowadays.
Fortunately, providing you have your important data backed up, it is not too traumatic and replacing them is not overly expensive (when compared to other major component failures).
Logic board failures can occur but, thankfully, appears to be rarer than drive failures. Whilst they can be expensive to replace, your data should not be at risk (unlike with a drive failure).
2.0GHz MacBook, 15" 1.25GHz/12" 1GHz PBs, 2xPPC Mac minis, 12" iBook G4,   Mac OS X (10.4.8)   Cube, 2xTAMs, iPod 4G & nano 2G, 1G & 2G iPs, AEBS, AX