I have the latest MacBook Pro. I lost the CD that came with it. I'm attempting to reinstall Snow Leopard using a retail disc purchased from Apple. I've tried booting it by holding "C" and by holding "OPTION" and selecting the disc. I've also tried reseting the PRAM. It goes the the Apple screen and I can hear the disk spinning. Then it just hangs there. Could this have anything to do with the fact that the computer came with 10.6.3 and I'm attempting to install 10.6 from the retail disc? Thanks!