Ive had the 17" 2.4 gHz for about 6 months now. The battery has been fine, maybe the odd health percentage going down sometimes but i've been happy with it. A few nights ago while watching a movie, it just decided to switch off (no ac plugged in) when i had just charged it too 100%. I think it was at about 82% when it switched off as i just checked it before it shut down. I tried to turn it back on but it would not have it!! I pressed the battery button on the bottom and it was only the first light lighting up and it was flashing. So i took it to a mac store and they said it has to be the software as its battery is working fine (they checked it in the store). So i formatted and re-installed and it was working fine but if i leave it for more than 20 minutes without power it will just simply turn itself off. Has anyone experience this before because i really don't want to have to send it off to apple for it to be checked as i have a lot of work on at the moment! Thanks, Dan.