regarding ibook g4 running os x 10.4 The screen on my ibook g4 randomly goes dark sometimes. The computer is still on as the fans are whirring, and I can hear the hard disks etc. While the screen is dark, when I close the lid it sometimes will not go into sleep mode. When it goes to sleep mode, when I reopen the lid, the screen is back to normal. But lately, closeing the lid won't even put the laptop into sleep mode and i'm forced to restart. I have no idea why this is happening. How can I fix it?? I realise my computer is dated, so I put it in this forum as it's the closest match for the g4.