Computer not booting after ifixit battery replacement

Hi, I just performed a battery replacement, using the Ifixit battery kit.

Everything went super smoothly, no problem.

Re-assembly was a breeze. Closed the case.

Plugged the charger into the magsafe, light came up orange.

Push the power button for 1, 5, 10seconds. Nothing.

Any amount of time on the power button does not seem to turn it on.

I proceeded with resetting the SMC. Saw the magsafe light go from orange to green and back to orange, but still no booting action.

Any idea for further troubleshooting steps ?

Thanks.