typing from my iPhone (!) after install, only get the spinning card- no startup. tried all startup key combinations and zapped PRAM. also ran disc utility and hardware check- hardware is fine all I get is nothing. noticed others reporting problems with the update on another thread, but my mac won't even start up. do not want to have to reinstall OS and 3rd party apps ! any suggestions? would it help to take to apple store geniuses- can they somehow bypass the update and get it started up?