MacBook Pro does not turn on

Hi!

So I bought my MacBook Pro back in december 2014, so it is not even 2 years old.

But now it won't even turn on. I tired a smc reset and it actually started, but the next day

my computer wouldn't turn on again. I gave it to a Apple service center, and got it back

2 days later, telling me the problem was "fail power" (not sure what it is called). The next day

my computer would not turn on again. Back to the store, and now they said it was a problem

with the motherboard, but after they have had it for a couple of days and runs some checks,

they now, again said nothing was wrong. The store had managed to start my computer, so I

got it back again. I used my computer that day and evening, but again the next day it would

not turn on again... Help me??