Shutdown your machine. Hold down the shift key. Poweron. Wait awhile Wait awhile while you harddrive
is being checked.
http://support.apple.com/kb/ht1455
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I'd let the machine sit for awhile in open firmware & see if it stays alive. Do a few prints.
Sometimes if volumes don't appear in Startup Manager (what you get when you hold down the Option key at startup), you need to reset the Mac's PRAM, NVRAM, and Open Firmware. Shut down the Mac, then power it up, and before the screen lights up, quickly hold down the Command, Option, P, and R keys, until the Mac has chimed twice more after the powerup chime. Then, before the screen lights up, hold down Command-Option-O-F until the Open Firmware screen appears. Then enter these lines, pressing Return after each one:
reset-nvram
set-defaults
reset-all
"The reset-all command should restart your Mac. If so, you have successfully reset the Open Firmware settings."
http://support.apple.com/kb/TS1812?viewlocale=en_US
How to eject a cd from the internal cd drive:
eject cd
List of devices:
devalias
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Restore Tiger 10.4 & Leopard 10.5 DVDs are available from Apple by calling 800-767-2775 as of January 20, 2013.
https://discussions.apple.com/thread/4720126?tstart=0