I desperately need some help. My iMac was running just fine until today when I restarted my machine and tried to get into Windows by holding the option key. Usually it works just fine, but today I got a blank gray screen. I tried it a few more times to no avail and then I let it boot up in Max OS and used the boot camp utility to see if it would work. I think I might have set the default start up disk to Windows. Now when I restart, I get the blank gray screen and holding option does nothing. 1) How do I get into Max OS? 2) How do I fix the problem and get into Windows again? Thanks in advance to anyone that can help!