Last night, my Safari froze my 2007 MacBook. So I manually shut it down by pressing the ON button. Upon turning it back on, I received the blinking question mark. I tried various things, like reinstalling, to try to save my information from my hard drive. No dice. The hard drive wasn't even recognized when I tried to reinstall. I took it to an Apple expert at a local store today and he said the hard drive was likely dead. So I bought a new one. The same problem- I can't install OS X because the hard drive is simply not showing up. In fact, under "Disk Utilities," it doesn't even show up on the left. Since the same things are happening to both hard drives, it leads me to believe that it isn't a hard drive problem. Does anyone have any suggestions? I'm at my wit's end.