Hello,
I'm new here, my english isn't very good, so please don't be strict with eventual mistakes I make.

I know there is another topic with the same problem, but I'm a noob, so I need more help like tutorials and stuff 
Maybe its another problem, but I don't know...

After trying to change OS of my CX (used this tutorial: https://www.reddit.com/r/nspire/comments/6a2cd7/tutorial_install_cas_on_tinspire_cx_works_on/ ),
I can't turn my calculator on, have a black screen.

Everything worked well until Step D 17.
My calculator showed me boot=Boot2 Diags, tried to change it to boot=Diags Boot2, but it didn't work.
After that i tried random stuff to install ControlX, but this didn't work either.
So I jumped to Step E (second time) with skipping 1, reset my calc with ctrl.

No i have a black screen,
ESC+MENU+-+RESET didn't work, DOC+ENTER+EE+RESET too.

How can I revive my calculator  ?

Thanks for help!