My dual G4 running System 10.03 has decided to stop going to sleep. Worked fine up until a few weeks ago. I have zapped the PRAM and reset the NVRAM. Sometimes it goes to sleep after zapping the PRAM and sometimes not. I close all the apps and still it refuses to sleep. The only way it will sleep is if I log out. I have no 2nd party cards in the G4. Seems like a software problem. Any ideas?