I bought a MBP in Jan '07 and lately I've been noticing that it freezes up very frequently when running off of battery power alone. I use the computer five days a week at work running off of the wall power adapter while the battery is in (~9 hours) and then again usually at night before I go to bed while watching TV for an hour or so and periodically on the weekends. The problem NEVER occurs while I'm plugged in to wall power, but when I run off batteries it can strike at any moment. I thought it had to do with running a particular application (i.e. Adium), but I haven't been using any chat programs on it in a month or so and it's still going on. I've had it freeze up on me up to three times in under an hour just running Mail and Safari. It's a hard freeze. Even the backlit keyboard stays lit up and the only way to get it working again is to hold down the power button to shut down and then power back up again. I know that running wall power while your battery is in wears on your battery after a while and diminishes its capacity, but when these freezes are happening I have over an hour (or two sometimes) of battery life. Could these issues be related to a bad battery or maybe I need to re-install Leopard for some reason (which would blow)? Any thoughts?