Thanks Meter 42
Join Date: Oct 2007
Location: Somewhere out west
Might not be good
If a charged battery does not bring it back to life, your phone might be toast. What you are describing is exactly the behavior I saw when my emmc chip went out on my first Vivid. JTAG would not talk to it either. No repair was possible short of changing the main board.
Hopefully, yours is just a charging issue. Good luck.
On the bright side, it might not have been anything you did. Mine died just as suddenly for no cause at all.
Motorola V620->HTC 8125->HTC Tilt2->HTC Vivid->Google Nexus 4->Moto X