Nokia X Flasher Tool
This Post you can get nokia x Flash Tool below on this post. before flash your phone at first make sure device doesn't has any type of hardware issue. before flashing fix your device hardware problem.
if phone auto restart, only show logo on screen. when you open any app mobile is stuck it's mean your phone firmware need update or flash. below green button click and wait until see the tool link. also if you need Nokia X Stock Rom Check here. if you need more help ask me on comment.