Chosen Solution
I ran my battery down. Now, after holding power button down for ten seconds, it chimes but won’t completely boot up.
Lets try doing a SMC reset: How to reset the System Management Controller (SMC) on your Mac let see if that resets the battery level setting within it. If that fails to improve things your battery may have hit its limit. How about running this app to see where you are: CoconutBattery. Take a screenshot of the main screen and post it here for us to see.
