I realize there are several threads on this, but none of what I've found so far has been useful. My 15" MBP simply won't make it past the Apple start up screen before I receive a power failure. I bought it in Aug. 2006, so I think it's probably the first model they released. Details: This computer came with one of the failing batteries that Apple offered a replacement on. I don't find myself away from a power outlet too often, so I never got around to replacing it and still using the original defective battery that holds a charge of about 10 minutes on a good day. The computer was working fine all last night and earlier this morning, but when I went away from it for a couple hours, I returned to find it had shut down, and when I tried to start it back up, it suffered power failure shortly afterward. I've tried the various things suggested on this forum that I could find to no avail. I've also gone through the list of resolutions offered on Apple's website for power failures, including resetting PRAM, SMC, and cleaning the power adapter head. It did make it further than the Apple start up screen before I reset SMC and PRAM, but I suspect that doing these things caused my computer to take a little longer on the first restart while it sorts itself out. It tends to last a little less than a minute before failing.