Mac OS X 10.6: If you see a gray screen at startup
If you see a blank gray screen after starting up your computer, you may have a problem with a firmware update. If you see a gray screen with an Apple logo (with or without a gear icon) and a flashing question mark, you may have a problem with missing, incompatible, or damaged software.
Note:To print these instructions, open the Help Viewer’s Action menu (looks like a gear) and choose Print.
Try the following:
Make sure the latest firmware for your computer is installed. Check the Apple Downloads website for the latest versions. If you recently installed a new version of your computer’s firmware, try installing it again.
If you have just installed Mac OS X 10.6 Snow Leopard, make sure your computer has at least 1 GB of memory and 9 GB of available disk space.
If your computer doesn’t meet these specifications, reinstall your previous, compatible version of Mac OS X using the discs that came with your computer or retail package.
If you are unsure of your computer’s specifications, start up the computer using the Mac OS X disc that came with it, and then open System Profiler.
If you are starting up from a DVD, make sure it is the disc that came with your computer or Mac OS X retail package. Discs from other Mac models may not work with your computer.
Repair your startup disk or disk permissions by starting up from your Mac OS X installation disc and using Disk Utility.