I have a early 2008 Macbook Pro pre-unibody that has just refused to warn me about it's battery life since May 2011. Before May, it used to pop and say "you're now running on reserve battery" and eventually it would put itself to sleep. Now, it just totally dies. No warning and no sleeping. I replaced the battery a few months later with a generic battery (not Apple brand) and the problem continued. I've re-calibrated both batteries multiple times, and today I installed a new HDD and reinstalled the OS from scratch and upgraded from 10.6 to 10.7. It still keeps dying. Any ideas would be greatly appreciated. This is driving me insane.