I can't believe... this mess because of an update!
I held the power button to the right for about 20 seconds but nothing happened.
Still that screen.
I don't think the battery's dead, before updating it was at 51% of charge.
but when I connect it to my computer it doesn't recognaize the reader, nor it charges.
I think I have to go to the shop, fortunately I bought it one month ago and my warranty is valid...
thank you all for helping me