Help HELP!, My phone isnt booting!

After the battery run out it wont start anymore!,how can i fix it!

I aleady did:
Hard reset

What i cant do:
TAke to assistance, because i've had root

My phone brand, according to the own phone, its made by LG in Brazil

Little last thingie:
Its turns on, but (as i hard reset it) it enters a screen called "updating android" when it gets in finishing, a sound plays (charger sound) and the notification and below (wich i dont know the name) bars, enter and leave in less than a second, it keeps saying finishing for a few seconds, and after a few time (i dont know how many) it shuts down.