How to reset the Parameters RAM:

• Shut down the computer.
• Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
• Turn on the computer.
• Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
• Hold the keys down until the computer restarts and you hear the startup sound for the second time.
• Release the keys

If the above method does not work then you can also try this one:

• Boot the machine into open-firmware by holding down the apple, option, "o", and "f" keys right after you press the power button to turn the machine on. Hold these keys until the computer boots into open-firmware.
• Type "reset-nvram" in the terminal.
• It will say that you have reset the nvram.
• Type "reset-all" to restart the machine.

Back to index