i erased my ENTIRE hard drive on my macbook air by accident. What i did was... I clicked something and it like delleted my entire hard drive. now when i turn on my air.. and my drive isnt plugged in... it flashes a question mark. and wont load an os!! I HAVE NO OPERATING SYSTEM!! and when my disc drive is plugged in... It goes to a screen where i can load up my Mac os x install disc. OR the network utility.. there used to be something called the "Macintosh HD" now its gone.. and I CANNOT INSTALL THE DISC! it says this software cannot be installed on this computer.. its leopard. so i cant do anything with my macbook air. please help me get an os working.