To anyone my Macbook Pro got this folder icon with question mark during boot up. I tried reinstalling my OS and boot from the DVD drive with Snow Leopard 10.6 but pressing the Control key to boot from DVD. I was able to click the OSX DVD icon. The only thing that happen was that it was stuck on the grey screen with the Apple symbol. How do I get to reinstall the 10.6 OS back on the hard drive?