I'm not going to completely rehash my old thread here http://forums.macrumors.com/showthread.php?t=402804 but in a nut shell here's what happened... I took my MP in 1/12/08 and they returned it 1/25/08 having completely replaced the motherboard and RAM cage (during reassembly they found the screws were stripped and had to replace the entire cage). Within 1 day the machine was shutting down and had a burning/hot metal smell. Took the MP back to the store 1/27/08. They put it on the bench immediately and found they had forgotten to plug the power supply fan in so the machine was overheating and powering down. I got the MP back on 1/28/08. I'm working on the machine tonight and I'll be damned but the same video artifacts start showing up again. Unfortunately, it's after hours for AppleCare but I'll call first thing in the morning. Obviously, I can demand to have the motherboard replaced again but at this point I don't want to be out of a computer again. Do I have a legitimate claim to ask for a new machine? If I don't, how many times does the motherboard have to fail before I can? This is getting ridiculous.