this sucks!! This is a replacement iMac for a G5 that had a sleep issue. My iMac won't sleep, just goes blank and I get the solid light. Looks like it is trying as the light is somewhat fading but I can still hear the fans spinning. Funny thing is, when I try to manually sleep it from the apple menu it takes about 45 seconds for anything to happen. I can sleep it, go open a program and start working and then all of a sudden it will sleep. I am so exasperated right now. I dealt with this stupid problem for the past two years to the point were Apple finally replaced my G5 now this!?!?!?!?