Phone Not charging/turning On

Hi, I used HTC 820 till it became zero battery charge. Now while charging the Red light blinks(It should actually be Red Solid) Hence it's not charging. And can't be turned On.

I tried pressing the following with and without wall mount charging

pressing Power key=20secs, 2 mins Etc

Pressing Power+Volume up key=20secs, 2 mins Etc

Pressing Power+Volume down key=20secs, 2 mins Etc

Pressing Power+Volume down+Volume down key=20secs, 2 mins Etc

Kindly help me, How can I get my phone back to charging.