3 Replies Latest reply: Apr 14, 2009 12:43 PM by realchemist
realchemist Level 1 Level 1 (0 points)
When attempting to start my iMac G5 (Ambient Light Sensor), fans come on but screen stays black. A couple minutes later, the fans rev up and run very quickly and loudly. This started happening when:

1. One day the screen showed a green question mark with a message indicating that the computer needed to be restarted in a box
2. Green lines were all across the screen
3. I forced it to shut down by holding down the power button
4. When I attempted to start it back up the fans started but the screen stayed black
5. After a couple of minutes, the fans revved up

This has been happening ever since. One time the computer started to the desktop but everything was frozen. I have reset the PMU, checked the diagnostic LEDs, reset the PRAM-basically everything suggested. Can anyone help? Thanks!

iMac G5 (Ambient Light Sensor), Mac OS X (10.4)