Phone wont turn on and flashes a red led

[Kairi Rose]

my phone was at 40% last night when i put it on my wall charger. i normally charge my phone over night. i woke up to it restarting itself this morning. it goes to the motorola m screen then the att screen then at the point where the phone should go to the home screen it flashes an red led and shuts down again.
when it is disconnected from the charger the phone does not respond to any of the power boots. it just does nothing
when connect to the charger i can hard reboot (power button and volume key) which pull up the andriod dude with his chest open and a red triangle with an ! mark on it. then after a very little bit the phone power back off
if anyone can help please.

 

[B. Diddy]

Welcome to Android Central! Your battery may be failing. Since the battery is not user-removable, you should ask yourself if it's worth the cost of sending it somewhere to replace the battery, or just buying a new phone, considering how old the Atrix is.