[Q] S3 I9300 Stuck on safe mode topic

Hi friends, after a lot of research and web searching i'm totally out of ideas and options :(

The problem: My S3 I9300 reboot in safe mode every time, is has been doing it since the past sunday. Another tip is that the volume buton down seems not work but only in CM Recovery or in the running software itselfs, it work correctly in donwload mode since i can reboot by presin the buton down. Another interesting fact is thath when I reboot the phone it start the led until it comes the Galaxy S 3 Logo (by presing the button down it power downs the led).

The posible solutions:

• Reboot
  Reboot after take the battery for a few minutes
  Reboot after take the battery out for hours
  Flash Custom Cyanogenmod
  Flash back stock s3 Jelly Bean (various ROM)
  Try to press volume up, volume down, menu capacitive, back capacitive keys and nothing.
  Take it to technical service (every one say it was software, but want to charge me a lot of money, talking about an hardware box "especially for flash samsungs")

I have done all the things that I expose before and possible anothers that I don't remember right now, and nothing works, it continuos rebooting into safe mode.

I have too read a lot on google and here and any of the posted solutions works for me.

Do anyone know how to solve this?

Really need help, thanks you all before hand!