HTC Desire 610 reboot loop

[AC Question]

My HTC Desire 610 suddenly decided to just keep rebooting tonight over and over again, it has been doing this for several hours now, the odd vibration here and there as it restarts. Have let the battery die but it just keeps doing it. Tried the factory reset however as soon as I hit the power button over factory reset it just displayed a phone with a red warning triangle and exclamation mark inside of it. Royally peed off with it and would appreciate any assistance.