Unhappy [Q] gs2 att i777 died while charging overnight

i had my phone plugged to the charger overnight about 2 weeks back. it was charging then, however it was completely dead in the morning.

tried holding the power button, nothing on the screen
tried removing the battery (had it out for > 1hr) and then inserted the battery back and tried charging/starting , nothing on the screen
i tried the power + volumerUP + volumeDown and nothing on the screen
Tried plugging the USB to a computer and tired to put the phone in download mode , but screen was dead.

i tried replacing the battery with a new one (from ebay) and it is still dead. the battery show about 3.8V when i check the + and - terminals using a multimeter.

it was working the night before and was dead in the morning, the phone is about 22 months old and it was running the original rom (i had rooted the phone about a year back),

i am not sure if the phone is bricked, please help guys.