Get to another mac and start up in target mode. Connect via firewire cable, start the bad machine holding down the "T" key. It should bring the hard drive up on the other machine. Get your data off first. Then run disk utilities.
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Get to another mac and start up in target mode. Connect via firewire cable, start the bad machine holding down the "T" key. It should bring the hard drive up on the other machine. Get your data off first. Then run disk utilities. Also check remedies listed on Apple's site for gray screen: http://support.apple.com/kb/TS2570
Try starting up in "Safe Mode", by holding down the shift key on start up. Let us know what happened. Also look at this link: http://support.apple.com/kb/TS2570
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Get to another mac and start up in target mode. Connect via firewire cable, start the bad machine holding down the "T" key. It should bring the hard drive up on the other machine. Get your data off first. Then run disk utilities.
Try starting up in "Safe Mode", by holding down the shift key on start up. Let us know what happened. Also look at this link: http://support.apple.com/kb/TS2570