G key is not working.

Hello friends,

A year ago, i subscribed to the apple beta tests program, and i have downloaded the mac os sierra, on my mac. Since then my G key stopped working. I know that isn't a hardware problem, because when i power the computer in safe mode, the key works perfectly only for type the password. Idk if somebody has solved here this problem before, but i can't find the solution, even in ifixit. Could somebody helps me? Idk what more can i do, and i don't have money to bring my computer to apple assistance, here in Brazil, is to much expensive. Thank you! And im sorry for the $@$* english LOL.