Symptoms: Put the system to sleep using the top left apple menu. Subsequently hit a key to wake up the system. Screen display comes back, but the keys and mouse are no longer being read by the computer. The only solution appears to be shutting down the system. However, if the restart is not done with the shift key held down it appears that the system hangs during reboot and never comes to life. Following the safe reboot I can reboot the system and everything comes up as expected. What I've tried (shots in the dark) 1. Repairing permissions 2. Booting from a different hard drive and running disk warrior Characteristics: 10.4.8 G4 867 dual, with 2G ram and 250G HD Screen energy saver set to: Display sleeps after 10 min Computer sleeps after 20 min. Frequently I find these do not take effect. Does anyone have any suggestions regarding a possible cause?