Last Of The Mac Whine?

Due to dental discomfort(had a back molar root removal yesterday ) I thought this afternoon I would turn my attention to the old iMac G3 and see if by installing an older version of Mac OSX on it I could get rid of the horrible noise. Google says it might work (due to the graphics chip/screenres). I doubt it but my knowledge of Macs is nonexistent so...and in anycase its cheaper than replacing internal bits to start with. 

>>>Update<<<

The downgrade to Mac OSX 10.2.3 didn't provide any relief, although the install itself went without a hitch even though the CD drive and the hard drive sound like they have had better days. As far as I can tell the whine is 'electrical' in origin...either the video inverter or the power supply? I've noted some specs down but the price of spares means I'll probably just scrap it or pass it on to someone else.