I've had my sweet new 20" intel iMac for aboput two months now & just moved to a new (old) house that has the old 2 prong elec outlets (no grounds), so i plugged in my imac and turned it on and the background keeps fading in & out, the window that's open keeps getting a light blue tint to it and i can't do anything when it gets that tint, also my mouse is constantly making a clicking sound! Very frustrating, it still works, i just have to put up with this weird light show that goes on. Has anyone ever heard of anything like this? Also, i did have an electrician come by to verify that enough volts where streaming through my outlet, and i did move my imac into the kitchen to a grounded outlet and it worked fine so maybe it does have to do with a grounded outlet? If anyone can help I would be most grateful otherwise i got to lug this thing to the apple store which i don't want to do. thanks.