iBook requires rest to boot

Very strange issue I'm facing with my iBook G4 (933mhz 256RAM). After loading the 10.4.9 update (my first mistake, I know) my system worked fine for a few days...until yesterday. The system froze, and hung at the login window on restart. After following the "Your Mac won't start up in Mac OS X" knowledge base article advice - doing everything from resetting the PRAM to repairing permissions to installing the 10.4.9 combo update to changing the prefs to running disk utility and fsck, the problem seems to be one of...rest.

The longer I leave my system off, the longer it will run on startup - though usually no more than 20 minutes. If I leave it off for an hour or so, it'll boot up fine, but freeze soon after loading everything.

Disk Utility and fsck found no problems. Unfortunately I do not have my Tiger install CDs with me, as I'm traveling this week, so I've been unable to try and boot from the CD and run the hardware test. But I am concerned by the nature of this problem.

Thoughts or suggestions? I am unsure whether this is specifically a 10.4.9 issue, so I've posted it here, though 10.4.9 does seem to have been the trigger, and as a result I've told all my Mac user friends to avoid that update until Apple resolves the myriad problems with it.

iBook G4 Mac OS X (10.4.9) 933mhz 256 RAM