Why does my htc dna only work connected to the computer?

[AC Question]

my htc dna randomly did not come on last week and wouldn't turn on. when I turned on the phone it would stay only on the start up screen. I thought that the battery was dead so I charged it and it still would not turn on. then I tried different cords even my orginal cord and it would not start up. I also pushed the power button and the volume down button to the reboot screen and the reboot did nothing. I then thought to connect my phone to the computer and turned it on and went passed the start up screen and worked but once I unplugged it from the computer my phone turned automatically.then I thought it must be because the battery is completely dead so I bought a the official htc dna battery took apart my phone and replaced the battery. let it completely charged and still was doing the same thing. I have ran out of options, please help if there is something that I didn't do.

 

[B. Diddy]

I wonder if there's a problem with the wall charging plug--maybe it's not really charging your phone, while when you plug the phone into the computer via USB, it's actually starting to charge the battery (albeit very slowly). Try a new wall charging plug.