My MacBook Pro mid 2012 13" shows only a white screen

Hi

I have a MacBook Pro mid 2012 13" and it has some issues.

It first started about a week ago with some unexpected restarts. Then I start to see the prohibitory sign. I tried everything I could with Command+R. But what ever option I would choose would make my laptop to freeze. Note: I would have to hold the command+R for about 30 minutes until would get in recovery mode.

The only thing I was able to do was to delete everything from my HD with some commands I read here on forum(I can't remember now). After that was done, my laptop restarted and shows only a white screen after I hear the chime.

I tried all the keyboard combinations I found on internet. I held some of them for 30+minutes and nothing.

I bought a new HD, I used TransMac so i can make it ready for my MacBook Pro (format+restore image). I did the same with the old one. I created a bootable USB stick. Tried all keyboard combinations again and again and nothing. Still the white screen. I reseted the PRAM for couple times as well.

I would gladly appreciate if any of you has any idea how to bring this laptop back to life.

Thank you