laptop wont start after themal paste changed

[blacknitro]

So i aplied some mx4 on my laptop cpu and gpu (im not a newbie) cleaned my fan, mounted and it worked, -10c on cpu and -5c on gpu, my brother played for 30min, then went to bed, today (next day) he played a couple of hours, then he turned of the laptop, 1h later, he came back and the laptop wont turn on, no hhd spining, screen off, and the fan started to spin fast (max rpm) after 30seconds, but the air is cold. i removed the ram, hhd (btw it also have an ssd on the dvd tray) disassembled everything, changed the paste (the previous one was good, no paste went outside to the pcb) , no burned smell or anyting fried, assebled everything and nothing, does anyone know whats might happening? its a asus k550xj

 

[captaincharisma]

bad paste or not applying it correctly perhaps?