I was in a lecture the other day and I turned my MBP on, and instead of starting up it gave me a folder with a question mark on it. I tried clearing the NVRAM and PRAM and then tried running the restore DVD but the hard drive didn't come up in disk utility. I tried my PS3's hard drive to see whether it was the hard drive that was faulty or the MBP, and the PS3 hard drive showed up so clearly it must have been a dead hard drive. I ordered a new hard drive and it arrived today so i tried it out but my MacBook Pro still can't see it in either the OS X setup or in disk utility. I thought perhaps this new HDD was faulty so I tried it in my PS3 and it worked absolutely fine. I then tried the PS3 HDD in my MBP again and it showed up in disk utility just as I would have expected. Anyone got any idea what might be wrong?