I will take it to the nearest place where it can be repaired, unfortunately Novi Sad is too far from the place I live, and so is with Belgrade.
This R1AE037 firmware is too buggy, the phone locks up very frequently, it doesn't do that with R1FA037.
Again, thank you guys, I will tell you what the cost of repair was :)

@KingOfKingz1
It's probably what you think, an EROM problem, but does the red light on the power button flash? If it doesn't flash than the problem could be in the connection between the charger an the phone and its battery. I always look to try the solution for such simple things before you say to yourself that you can't do nothing and that you have to hand it over to someone with more knowledge about these little things :D
Hope it's not the EROM :)
Pozdrav drugovi :P