Loud hum when Imac sleeps

i've been using my imac g5 for a few months with no issues what-so-ever. just recently i've run into one major issue. when the computer puts itself to sleep...i get a loud humming noise that will not stop (i think its the fan running. the power button is disabled and i have to unplug the computer and plug it back in to restart it. any idea what the problem is? i think i may have changed the power saver settings just before this issue surfaced, but i'm not sure what would cause this to happen.

What it's doing is going into sleep mode and this is normal. You should be able to wake it up just moving the mouse or pressing any keys on the keyboard. What I want to find out is whether it's hanging up when it goes to sleep or if it will wake up normally as it should regardless of the humming sound. To check the Energy Saver settings go into System Preferences/Energy Saver.
George

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