First thank you both. I have used the way commented bonk (because cmd and me are not friends), but thanks to you. I have again my nexus. But i am now so scared and I waited a little before returning to do these things (or at least with a good translator) thanks again.
My problem is resolved.
To DowntownJeffBrown i sorry understand me, I was puzzled and I found no way to delete it. by the end of the text that I had got wrong.