iMac G4 was working fine all day... I plugged in a USB digital camera and then the computer shut down. Now the keyboard and mouse will not work at all. They are not even getting power-- the red light does not turn on/tried different mouse and keyboard, same thing. The comp. itself is fine because I can access it through the network, but the USB ports are unresponsive. I have tried unplugging/plugging back in, ect... I have tried to reset the PRAM but can't because they won't work. Suggestions?? Thanks.