HTC ONE randomly shut down now requires password to decrypt storage..

[Bisonmom1]

I have had my ONE for a couple of months and had MULTIPLE issues but this one takes the cake!   I was in Wal-Mart and the phone randomly shut down with a full battery.  It would never reboot on it's own so I had to push power down and volume down to get reboot screen.  When it finally restarted, it came up with a screen that says "Type password to decrypt storage" or "place an emergency call".  I never set a password so am unclear on what to do from here.  Tried to factory reset but it doesn't work.  Any advice??