I've read that the Apple instructions are incorrect for some models. This might be worth a try.
'''Resetting the System Management Controller (SMC) with a battery you can remove'''
Shut down the computer.
Disconnect the MagSafe power adapter from the computer.
Remove the battery.
Press and hold the power button for 10 seconds.
Release the power button.
Reconnect MagSafe power adapter.''' ***DO NOT RECONNECT BATTERY YET***'''
Wait 5 seconds
If light turns green, then put the battery back in
wait 5 seconds
Press the power button to turn on the computer.