Many moons ago I bought a 12" 1.33Ghz Powerbook - I was very happy with it apart from the battery - it would only last around 10 minutes but appeared to hold that charge intact if unused for months. A year or so ago I reset the PMU and the battery 'remembered' it had more life and would last 40 minutes. Today, I picked it up - being a few days since I used it last but it wouldn't start, the battery had folded and it also refused to charge. After resetting the PMU I charged it fully and left it running to calibrate the battery - now it's running for 2 hours 9 minutes! I don't know what, if any conclusion to draw but thought I'd share.