I Can't Reboot my Phone (Nexus 5)

A

AC Question

Hi !

a few days ago, my nexus 5 suddently stopped working. it stayed closed when it was on battery, and whenever i charged it, it would just boot up without me touching anything and closing a second after; i could only see the google logo and then it closed, then booted again, then closed, again and again. After i tried a lot of things, today i somehow managed to go into the boot menu thing (with the green android logo), and i pressed start. after that, the google logo showed up on the screen for a long time, like 15 seconds, then the 4 points that move around showed up, as usual, but it's been an hour and a half and it's still booting up. what can i do to fix my nexus ? thanks