since i've posted this thread,iwas goiing for reinstalling os via NSU but get stopped at "15 minutes remaning" so i waited about 1hour,i got angry and disconected my device,luckly it is still working,but that's because (i think) NSU has blocked (start to do nothing,stop running) so i don't know if to try second time,i wil wait for you all to come whit an ideea.Thank you all!!