Chosen Solution
I’ve tried disconnecting the battery and reconnecting the battery still won’t start. Prior to this I was downloading ZOOM. During the download I closed the lid of my MAC and walked away. Now won’t start.
When you connect the MagSafe charger what is the color of the LED? Amber or Green If its Amber let it sit for at least 8 hours so the battery is charged, hopefully by then the LED is Green, If not then you likely have a worn-out battery, even still see if the system boot up. To isolate the issue more, disconnect the battery again, with nothing connected, press and hold the power button for a good 15 seconds so you can fully discharge the logic board, now with the system on its side plug in the MagSafe charger your system should spontaneously boot up, let it finish booting and do a proper shutdown. Now reconnect the battery and restart the system again did it boot up? Did the system fail to spontaneously boot up? If you are able to install this gem of an app! CoconutBattery take a snapshot of the apps main window and post it here for us to see Adding images to an existing question so we can see the system charging and the state of the battery.
