G4 won't fully boot, we turned it off for the day, came in the next morning hit the power button and waited while it booted. It got held up at internet services, we unplugged it from the network restarted. It would boot all the way up so you could see the desktop wallpaper but then the black "you need to restart" screen would pop up. Anyone have any ideas or an troubleshooting to figure out was going on? Any advice would be helpful considering I'm a new mac user.