Hello there,question for the community. Last night my mac book (early 2009) froze and became completely unresponsive. I restarted it and got the grey apple screen with the forever spinning circle. I have decided to call it a loss and wipe the HD and reinstall the OS, but I have tried booting it from the DVD and when trying to wipe the HD i get a message saying the drive cannot be unmounted. As I can't access the drive I cannot see if there is anything running or what's going on. Also, a few notes on some strange behavior that is probably related. My mac book has not been able to restart on its own for the past month (it must be powered down by pressing the button) it also has been doing this thing where if the battery dies, it doesn't boot up after being plugged in until a few hours later. I'm suspecting that the HD is dead, or possibly the logic board, but i'd really like that to not be the case, any input on how to wipe the HD and reinstall the OS would be awesome, thanks!