This can also happen with a dead PRAM battery. Try replacing the 3.6 volt 1/2 AA lithium battery. Next do a PMU reset, here's how: http://support.apple.com/kb/HT1939
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This can also happen with a dead PRAM battery. Try replacing the 3.6 volt 1/2 AA lithium battery. Here's how to do it: http://www.youtube.com/watch?v=KS-XDtQwN_8
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Next do a PMU reset, here's how: http://support.apple.com/kb/HT1939
This can also happen with a dead PRAM battery. Try replacing the 3.6 volt 1/2 AA lithium battery. Next do a PMU reset, here's how: http://support.apple.com/kb/HT1939