Hi I have imac 24 6.1 starting up with continuous flashing folder with question mark on it? i cant see any other thing on it. i tries some tips by pressing and holding comand+R or comand+option+P+R and shift keys but none of them worked .... still blinking folder. i am using third party keyboard. also is it possible to download apple software from internet and used the downloaded cd to reinstall osx on this mac? regards Zia