I have a MBP 3,1. It's currently running 2.2 GHz, 200 GB 7200 RPM drive, and 6 GB of RAM. I had a recent, imminent, catastrophic, totalitarian, heart-wrenching failure about a week ago, which I was fortunate to have had repaired by Apple. I am curious about the cause of the failure and whether or not my 4 GB SODIMM might have anything to do with it. The computer has failed on 2 distinct occasions. Here are facts. Both failures had this characteristic symptom: power button registered no apparent activity. Holding down power button made something in the machine have a faint clicking noise, which sounded like it was coming from the optical drive. The actual origins were unknown. Failure 1: Occurred several months ago, pre-6 GB (but with 2x2 GB SODIMMS that I installed a year ago), during a new hard drive installation. Put in new HDD, would not boot up. Tried to reseat all the connections, no go. Replaced original drive, booted up fine. I concluded at the time that it was the drive, but the company I bought it from tested the drive and said it was fine. The replacement drive they sent worked fine, by the way. Failure 2: Occurred imminently the other night, during routine tasks. Swapped memory in and out in various configurations to no avail. Removed the HDD and tested in an external enclosure, worked fine. Replacement details: Apple replaced the logic board (605-1790), something graphics related (675-0075), AND both of my 2 GB aftermarket DIMMs (333-0709), which they said did not pass a memory test. So ... any ideas what happened, and what the 4 GB DIMM might have contributed?