Macbook does NOT power on / boot up anymore!

Today I carefully took apart the top case of my macbook to replace the inverter cable.

After I replaced the inverter cable, and before I re-assembled the parts back, I checked to make sure that everything worked fine. It powered on and the LCD worked again. Yay... So I went ahead and carefully re-assembled all the parts and screws back.

I pressed the power button, but surprisingly the macbook no longer power on or boot up! I get absolutely no noise, no reaction, no response whatsoever.

My battery is full, and the power cable has the green light when plugged into the macbook. Also, I am sure the metallic strip from the bottom of the topcase is connected to the logic board.

Could someone please provide any insight/advise? Could the logic board be broken? My warranty ran out a few months ago

 

Thanks for your quick response. Yes the power ribbon is still connected to the logic board, but still no power.