I've got a late 2006 iMac, and I think the logic board is bad. I'm getting failing video ram testing from Tech Tool Pro, and took this to my local Apple Store and was told the same thing. I'm almost ready to chunk it and buy a new machine, but found another iMac owner with a busted machine. He's wanting to sell the logic board and the guts of the machine as his screen is busted. The sticking point is that the iMac he has is a 2008 model. I don't know if I can use the guts from a 2008 model in my case or just the logic board, or no parts at all? The seller has an iMac with a busted and removed monitor. I've had this machine for about 3 years, but I was dumb enough to pass on the Apple Care extended warranty.