Notebook won't turn on after placing the top cover

Registration date
Wednesday September 10, 2014
Last seen
September 10, 2014
I have an ASUS k55A laptop whose gpu was broken, so I replaced the motherboard.
After placing and wiring all the components together and before placing all inside the laptop I tried to turn it on, it works flawlessly
The problem is when I try to assemble the top part (which have the keyboard and power Button) the laptop won't turn on. also, with the pc on, tried to place 3 corners except the one with the power button and still works, but when y place the top corner of the case it turns off again.
I don't know if the something is making false contact with the motherboard or the power button. after assembling it all together 5 times all seems fine.

Do you have any similar problems or know what i'm doing wrong ?