Whenever I leave my Power Mac G4 MDD on standby for a few hours (I set the display to sleep in 5 mins), whenever I move the mouse/touch the keyboard, it doesn't wake up anymore. The Fans and Power LED is still on but it is just stuck there. All network activity has stopped (when I'm downloading) and even the keyboard won't respond when I press caps lock. Whenever I use it however, it's just fine. It only freezes a few hours when idle. I haven't added any new hardware lately and it was just fine until a few days ago. Any ideas what's wrong?