MacBook Pro, 15" (Early 2011), not booting
Try Resetting the  SMC (if you haven't already, and see if that changes any of the mentioned behaviors)


Shut down the Mac.
Plug in the MagSafe or USB-C power adapter to a power source and to your Mac.
Using the built-in keyboard, press Shift-Control-Option on the left side of the keyboard, then press the power button at the same time.
Release all keys, then press the power button again to turn on your Mac.


The SMC or System Management Controller can require a reset and exhibit similar symptoms when malfunctioning. If this doesn't help, I can only suggest there may be hardware damage somewhere or possibly latent water damage side effects manifesting themselves.