Al MacBook 15" unibody with 4 gig RAM and up to date snow leopard. My notebook froze up earlier requiring a hard reboot. During reboot it got stuck at the white screen making the Mac tones over and over again. I had to hard reboot again and now I can't get the OS to boot up. The computer turns on but nothing happens other than the HD light on the front of the device. I suspect the computer froze in the first place going into low battery induced sleep. Given that fact I gave it time to charge but it is still not turning on. I love apple products but i avoid apple stores like the plague, so if anyone has any DIY advice that would be great, thanks!