My white Macbook is randomly losing power and shutting down, even with charger and battery in. It makes the sound that when you hold the power button to force shut down the mac. When i boot my Macbook, it would make the chime, then suddenly lose power and shut off. Sometimes this would happen before the chime or mid-chime or when I've logged in. After losing power and shutting off, it would boot again, then shutdown, etc. I've been able to observe this problem with different batteries installed, with charger plugged in + battery and just the charger plugged-so i don't think it's not the battery's problem.