I don't care enough about this iMac to do a motherboard replacement. Right now, on the Apple Discussions thread, we think the cd drive is failing. I posted a WTB/WTT ad on the trading section on these forums for a firewire cd drive. (I opened this mac up recently, and when I pick it up, I feel lost screws jingling) If anyone of you have a spare drive, I'd like to buy it from you, or trade something for it.