@Elaine, hi. i have come across this community and well, i've also created an account just for this very reason. almar here asked the right question and still hasn't gotten an answer.
See, i'm currently experiencing the same problem. my phone, Flash 2, only shows up at the start up screen where it says Flash and powered by Android. But seconds after that, it shuts down and turns on back to that very screen again and does this until it just stops because the battery probably had fully drained. Please give us a feed back on this.
this happened because i tried to update the OS to Marshmallow which by the way ended up being corrupt, resulting the problem i got myself in. thanks for that.