Mac won't power up

Problem

Issue with powering on MacBook Pro Retina.
Tried a hard reset (hold power button down for 10 seconds).
This did not solve the issue.
When the power button was pressed, the Apple logo light on the laptop was on.
Toggling Caps-Lock did not power on or off the light in the Caps-Lock key.
There was some heat coming from the laptop when touching the bottom of if.

Solution

The solution was to reset the NVRAM.
To do this, do a hard poweroff (hold down the power button for about 10 seconds). Verify that the Apple logo on the laptop lid is not on.
Now press the power button.
Immediately after pressing the power button hold down the following keys. Command, Option, P and R. You will then hear the start up sound play.
Keep holding the keys down until the startup sound plays again, or till the login screen is displayed.


More details about this can be found on the Apple website https://support.apple.com/en-us/HT204063